Thanks for the update!

Btw, I just ordered a 2H!
Might probably just get one unit to cover the bedroom? Most purifiers should be able to cover like 200-350 sq feet.

HEPA filter is bare minimum but a carbon filter is optional IMHO but most purifiers come with it.

I would advise to focus more on the running costs of maintaining the purifier, i.e. the filters. They're usually expensive.

Other factors to consider is size, noise at each fan level, whether it has pre-filter (to extend the life of the HEPA filter), ionisation tech like Sharp/Panasonic, app support.

Do not trust when manufacturers say the filters can last up to x years.

For some odd reason, the higher end Sharp purifiers like the FPJ60LW or their humidyfing range, KCG40LW/KCG50LW/KCG60LW are bloody noisy at medium fan onwards. Tested several models from different places already which was why I gave up on them. Their mid to lower end range like the FPJ40LW or the FPJ30LA are fine though. And what was worst is that the rated noise level in the specifications was 45-49dB but in reality it was way much much louder.

Also, do call the service centre to inquire about filter availability after x years. This might be a real issue down the road as you might be stuck with an old model with no filter to purchase.

I personally called up Sharp and they said they usually will have filters available for the latest model for up to 10 years (estimate).

All you need is a good True HEPA filter that cover your bedroom as you spend 8 hours on your bed.

calculate your bedroom size. Buy Air purifier calculate using the performance are based on CADR (Clean Air Delivery Rate)
Use this for your need calculation
https://reviewsofairpurifiers.com/cadr-calculator/
L x W x H = Room Size

What is your budget?

Let us know more before we can dive deeper into your situation.
1. Calculate your bedroom size
2. Calculate your kids bedroom size
3. Calculate your living room size

DO NOT ever recommend an ionizer based air purifier to a person with asthma. Plasmacluster is just an another patented marketing name of ion technology (layman term ionizer) by Sharp.

Medical Center/Hospital wouldn't use ionizer, they use HEPA based technology but not Ion based tecnology for their air filtration system.

Asthma people need to avoid all Ion based tech air-con and/or air purifier.

Go look for Atmosphere Sky.
Highly recommended by doctors,  pediatrician and widely use in hospital now.

Get review from users who are using it.

Oh I thought you wanted 2 units to cover 1 bedroom. In that case, one purifier for each room.

Hepa filters work la, regardless of purifier brand, evident when you observe how dirty the filter is after x months.

Other features such as ionisation - Plasmacluster from Sharp, Nanoe from Panasonic or Virus Doctor from Samsung, is optional. I did not read too much into this actually.

Hardly any source that directly compares a certain model from Sharp vs Panasonic vs Samsung vs Xiaomi with detailed stats like a proper noise test, airflow/noise ratio, filter lifespan/price comparisons. Quite a bummer as the tech industry is the total opposite: pc hardware, mobile phones, etc.

Air purifier not a widely searched subject, hence, you don't see much reviews on certain models on the internet or youtube. Manufacturers not providing enough details, for example the noise levels at each fan speed or the minimum/maximum noise level was a little frustrating (Looking at you Samsung and Xiaomi).

This review is not bad though! https://pokde.net/blog/mi-air-purifier-pro-...e-air-purifier/

Why not check for ULPA purifier instead of HEPA, more refined at least 10 times.

www.chunghomy.com

That is your basic guideline where to start searching for.
1. 133CFM / 230m3h
2. 100CFM / 170m3h
3. 233CFM / 400m3h

Try get a Xiaomi Air Purifier 2C/2H/3H. These are using the basic standard affordable HEPA filter with micron size 0.3
Some high-end HEPA filter can go as small as 0.0024 like the one from Amway. Dyson also got as got their HEPA as small as 0.1 microns filter but with 70 CADR.
Coway/Cuckoo also got, but beware avoid ionizer feature, their product outright is not worthy due to spareparts are limited to purchase, while rent monthly option are easy to own but pricey in the long run. (Personally always recommend outright purchase if you can afford)

Since you have estimated RM2,000 for each purifier. Which mean you have RM6,000 budget to buy 3 air purifier.

1. Buy a "USED" Amway Atmosphere Air Purifier (Gen 2 - not the latest one) from Carousell/Facebook - around RM1,500+
- Flagship/Top high end grade air purifier (new one cost at RM4500++)
- Prefiter included (washable like air-con)
- HEPA filter micron 0.009 (everything you need is this filter - replacement cost around RM500, lifespan last around 1-3 years)
- Carbon filter to filter odour (you can skip to replace this filter if want to save budget - cost around RM400)
- CADR 400 m3/h to suit all your room size
- Allergy UK certified, AHAM certified (US standard), Energy Star certified (save electricity)
- Spareparts still sell by Amway in case need repair (Amway have track records sell their parts for more than 10 years after stop selling the model)
PS. I was still using this model for more than 6 years, it solved my nose allergy problem. And I even give my father use during his time resting at home after surgery from cancer. I personally high recommend this due to reputable company and parts availability even it is used model / no longer selling this gen 2 model. You can go to Amway HQ PJ to check this old model see still got display or not.

2. You should be left around RM4,000 budget
Buy a NEW Xiaomi Air Purifier Pro/3H (You can get 2-3 units with these balance of budget)
- all Xiaomi Air Purifier shared the same 0.3 micron size of HEPA filter (min standard for HEPA are 0.3 micron and below)
- Xiaomi should fit all your requirement as well. CADR 300 m3/h to suit all your room size
- The only cons that most people complain is their new generation come with RIFD to detect filter expire to force u replace otherwise not spinning at all (I just use for more than 1 month so no idea)
- and the filter lifespan is shorter than most of the competitor. is cheap to replace but shorter life span compare to those 1 years.
PS. I just bought 3H model, not much to comments, plan to put in baby room few months later. Currently using by me as well. You can walk in any Mi Store or Senheng to check display model.

3. There are some similar price range air purifier from Philip model AC2887. Their HEPA filter are much longer than Xiaomi. around up to 24months claim by them. The machine around RM1400+
PS. I also survey this before but end up I prefer the fancy feature from Xiaomi and cheaper ownership price.

There are still few out there like BlueAir 490i/690i but new one cost like RM3400/4000++ too ( with Hepa and high CADR)
Sharp majority come with Plasmacluster, as I said earlier, asthma must avoid all ionizer
Both Coway/Cuckoo most of the model come with ionizer, low end CADR are low.

Things to consider:
1. Performance (CADR, Technology (HEPA are most important))
2. Initial Price to ownership (outright/rent)
3. Cost of filter replacement (life span and price)
4. Warranty? How long and if not, replacement part / spare part still available?
5. Others certification (AHAM / Allergy UK etc)
6. Other fancy feature (smarthome/nightlight etc)

Might as well buy 2 units of Xiaomi Mijia Air Purifier 2H for the price. CADR around 50% more than it.
HN selling RM799 for Joy S. 2H selling around RM399 or lesser

Joy S no meter, no app, no remote. use it to believe it work for you. replacement around RM200 for 1 years (assume 12hours daily) - review from Google
2H got app to monitor. filter cheaper but last for 150 days only.

Since you already aware of the Joy S is inferior to 2H and you wish to try, ain't nobody gonna stop you lol 

Can look for used sets from FB/Carousell if want to try for the sake of try, but paying for a new one macam not worth for me.

Xiaomi Manual Speed got 1-2-3 only, but you can automate it using app re-set it to max speed if you wish for every hour.
IF: 08.00PM
THEN: Set to MANUAL
IF: 10.00AM
THEN: Set to MANUAL

I have no problem for this since I don't always open turbo 3 speed for more than half hour.

There are model doesn't come with RFID if that is a concern for you but forcing you to change filter is good for our health anyway. We human always have laziness or procrastination to delay our purchase filter.