On the other side, Realme and Samsung low end got worst original camera than Google Camera, just using the Gcam alone without post-processing(means no support for qualcomm ISP on the multi-frame post-processing because of Processor) got better image than the original one.

The noise, will be acceptable by using Gcam, that's compare with my original camera app on Xiaomi Max 2 and Huawei Y Max.
If compare with the RM 1599 Mate 20 Pro, nah.

Just, ported Gcam got lot of bug that will getting you hang on shooting sometimes, also no support on Video side, 720P only.

For simple meaning, no clear text that print on the biscuit box after 2 meter capture using the camera.

And my requirement is, at least a acceptable noise reduction algorithm on original camera, and also allow the user using it with manual mode is one of my requirement, so far any new phone grabbed by me don't not meet the requirement of acceptable noise reduction, only Max 2 is my best camera on my hand so far(expect to test incoming Redmi Note 9s).... but low resolution is hurting me la.

Not saying no support of HEIF and HEVC to saving the space of your phone, but Realme and Samsung better than Asus Zenfone Max Pro (M1) which, AOSP camera lol.
But Max Pro (M1) allow you to enable the Camera2 API to use with GCAM, also third-party camera with support of HEVC as it is Qualcomm chipset.(OpenCamera, free solution for Qualcomm chipset to enable support of HEVC, HEIF not yet as too less phone with hardware acceleration of chipset supporting it.)

Also, incoming Android 10 which is in beta, sadly because of coronavirus, guess gonna wait for another months, and I guess Android 10 is last ROM for Realme C1, 3 and Asus Zenfone Max Pro (M1).

For Color OS, the available feature compare with AOSP are, Smart Assistant with support of weather, calander, step tracker, Photos and Favorite Contacts.
Detection of fake base, safe keyboard, Lock screen Magizine, status bar network speed.

Fake Contacts, call history, messages and events can be providing to Apps, Blacklist Whitelist, App lock, Kid Space, Private Safe.
Assistive ball(know as white dots), smart sidebar, hold 0.5s for Google Assistant etc, and also three finger screenshot.

Support of Game Space which allow you to enable performance mode, and also App Cloner, but I don't testing for duplication detect, so far I know the MIUI is best on prevention of duplication detection on App Clone.

Also Car Mode and Riding Mode.

The new feature after update in half of year is, Android 9, Dark mode forces on all apps, and also support of Swipe gestures, which swipe from left/right to back, and home/hold to multitask from bottom.

But strangely, same update date, only Realme C1 got Swipe gestures, no support of it on Realme 3.....

Also strange is, no support of Display Size on Realme 3, but it is available on Realme C1, huh???

Most of the feature is available on India only, like the latest VoWiFi, as I don't got Digi, so I can't test on this one.

The bad side is, ads from Theme and also App Market, can just disable the notification, not a problem.
Strange Battery optimize that sometimes 5% for daily standby, sometimes 10-15% for daily standby without any WiFi enabled.
Camera settings only access from Settings - System Apps.

Disallow of user to disable the AutoStart on Facebook and Messenger, a restart will re-enable it.

The worst one, need user to enable vibration on call for silent mode on the APP notification, with the "Vibrate When Ringing" and "Wibrate on Silent" enabled inside the Sound& Vibration, nani!?

First time when I found my phone got miss call, and I take a look on it, what? no vibrate even I enabled it!?

Also, keep reset the Animation settings on your Developer, inform of you to disable Developer Mode period(like charging your phone).
When the first time I get this phone it is worst, a Red flashing bar warning that you had enabled Developer Mode.. ok...
But then, I enable subtitle, and warning me I enabled Assistance Mode, what!?

Lucky it is changed after a few update.

Fun part, you can enable the Vibrate of system UI notification, so you know it is charged full, or Google accessing your GPS location per 5 mins.
Also you can use the Google Face Unlock.

So, if you want to get a similar exp like Redmi, you can get on Realme, just I remind you that the inconstant of settings!!! and sloooooow charge speed is something you need to take care of.
But I guess if you got fast charge high end, the 5 watts slow charge should be fixed.

Also, new feature incoming each big update is part of the exp like Redmi.

For Samsung, nah, RM 1k+ for A30s, forget about it.
As it is not on my hand, the only thing is, easy to failed under-screen fingerprint unlock, and 720p.
But the good side is, it don't scare of the constant hand wet finger, as the dirty will getting swipe by your daily use lol.

Redmi?
If not unlock and flash to China/EU ver, it is not, the BEST exp of a MIUI...
But acceptable la.

Weekly Dev update is my best exp, also quick fix on the support of capturing the Taobao Shipping info, also Mi Push support, best for battery life, no need for the apps running on background but still notification received, unlike other phone, but just me like it la lol.

The Mi Push, sadly only China app supporting it, Lazada support it, but they are supporting it in a wrong way, which require you to keep Lazada App running in the background to receive the notification, just like other FCM push application, Google did it wrong, and not gonna change it.
Bad for battery life I will say.

EMUI?
Also forget about it la, based on my sister, P10 getting bad and bad battery optimize after each update, but I will say it is ok now for daily use on latest flagship, just, don't game on it, you will cry on battery life and also 720p forced downgrade resolution.

What's worst on Realme and Samsung hardware?

Realme, no 5Ghz of WiFi support, but the chipset support it, what!?
Redme got it since Redmi Note 4x!!

Bad exp if you upgraded from Streamyx to UniFi 30M, you will get constant 2.4Ghz WiFi interrupt from the neighbour.....

Samsung?
Worst battery optimize on chipset, stay on homescreen eat 300mA from battery(AccuBattery), only 100-200mA with my Mi Max 2 Qualcomm 625.