Haha deco division sohai product manager purposely limit cannot split like usual

So better buy Asus AI mesh
By default deco only have 1 visible ssid only (of same name)

Guest network function can 1 more visible ssid (so 2 ssid visible)
But keep in mind deco mesh system also broadcasts hidden ssid for mesh purposes. So maybe 3 or 4 ssid in total depending on model

Well i means actually is most dual band router by default having 2 ssid for 2 different bands (tri band router will have 3 ssid) excluding guest functions
But if turn on the "band steering" or "smart connect" function, it make the ssid be the same for both bands, and deco by default enforce such feature by default
To turn off band steering or smart connect feature, unfortunately there is no such switch in deco. Instead you have guest function also used for the workaround. Because in one ssid can individually turn off either 2.4 or 5ghz band, so you can do so that main ssid use only 5ghz and "guest function" ssid use only 2.4

TP-Link argument is because their band steering and roaming is so good, you shouldn't need to manually switch 5GHz and 2.4GHz.

And, most of the time, it's true. Deco roaming and band steering is really top notch with almost gapless switching.

But there are still some really weird IoT stuffs out there that wouldn't work properly on such network. For more complex scenario, I would recommend ASUS AiMesh.

All of these are standards based (or they won't won't work with any random device.) With exceptions like Ubiquity's now-deprecated "Zero Handoff". Now they have "Fast Roaming" that is not 802.11r but I've no idea what this actually does.

Client steering sounds like 802.11k and/or 802.11v.
I guess node steering is like client steering but for nodes. I assume nodes are APs. If 2 nodes only, then no point lah.

Band steering is always good to have. Most clients nowadays will automatically prefer 5Ghz over 2.4Ghz anyway.

Having 2 SSIDs for 2.4Ghz & 5Ghz is kinda like human band steering.

But most important to remember is that the AP never makes the decision, it's always the device that decides which BSSID it wants to connect to. The most the AP can actively do is to kick the client off if its signal is too low. I do this on my Mikrotik APs bcos Mikrotik wifi sux, no 802.11kvr.

Lastly lowering transmit power almost always help. MY max is 30dBM or 1000mW. I have both my 5Ghz APs at 25dBM (300mW) and my 2.4Ghz at 20dBM (100mW.) This largely depends on your house and neighbours.

As blacktubi mentioned, Deco M-series works pretty well. That's my go-to APs for family & friends. Can't separate the SSIDs but that's how I like it anyway so that's fine. The only complain I have is their SmartDHCP (in AP mode) which can't be turned off. It comes on when it's unable to obtain an address from your main router and starts assigning addresses to everyone. I think they may have put in an on/off toggle for that now.

D-Link product?   
Asus for better firmware updates.
TP-Link cheap for performance but expect lesser or no firmware updates.

ASUS>TP-Link>D-Link

2.4GHz with lot of interference memang speed macam siput

for any wifi or wireless (including 4g/5g) do not trust the theorical speed

there will be tons of overhead for wireless. wifi 4 (802.11n) is notorious for too much overhead and also more suspicious to interference. 150mbps adapter is most likely 1x1 antenna which will worsen the reception.

150mbps 1x1 antenna at 40mhz. usually to avoid interference most routers default to 20mhz which will half the speed to 72mbps. irl speed at 40mbps is normal due to overhead

avoid this model especially dual core one

this model notorious for overheating
tp link t20u plus is good

No, adapter is like receiving client. There is absolutely no need for tri band. However there is now new technology that can make use of 2 bands at the same time if router is set to smart connect (same ssid for 2 bands) to help increase some speed. Intel latest AX411 is capable of that using smart dual connect technology (DCT), for example.

okay lah ac1300 is also good enough. but this design no high gain antenna. if go for tplink t4u got high gain antenna
if using a wifi 6 adapter in a wifi 5 network, will it help in speed in real life comparing to wifi 5 adapter although i know that the speed will be limited to wifi 5. however, will it still help in anyway?
not at all significant, still same, maybe slightly better reception

your pc in your room and mesh wifi router in your room too why no connect ethernet cable to pc? 😅

Any recommendations for a wifi extender?

House type: Condo
Size of house: 1 floor, 1500sqf
Features required: a wifi extender to address wifi dead spot in my gaming room or lounge room (depending where I place the main router). Prefer low latency and not to technical to setup.
Number of devices connected to WiFi: 3-4
Internet Speed: 100mbps
Budget: <200 MYR