Honestly, Custom ROMs have been in decline of usage since few years.
There are also Other ROMS like Pixel Experience, PixyOS, Havoc, evolutionX, PixelOS, Paranoid, Derpfest, CrDroid and lot more.
The reason for the drop is due to a combination of reasons like better OEM UI, unpublished Kernel code (Chinese OEMs, Mediatek), locked bootloaders and Safetynet issues.
Before i got my Pixel 6 Pro, i've been running Custom Roms on everything. The Pixel 6 Pro is probably the first device, i'm actually okay running Stock. It just does what it should. And i'll be honest, the hassle of getting it to work properly (Banking, Netflix, etc) is just too much for my everyday phone...Google really did a number on that one, both positive and negative. I kind of hate it...
That isn't the only factor though. Take OnePlus, for example. You can still unlock their bootloaders, but if you check out XDA you'll see that their hasn't been any custom roms for a OnePlus flagship since the 9 pro because they stopped publishing the MSM tool, so the risk of bricking the phone is too great.
I used to turn to custom roms to extend the life of my phone. My first smartphone didn't get an official update after I purchased it for example. The custom roms often made the phone snappier too.
These days I'm on a mid range Samsung phone released almost 4 years ago and it's still getting updates.
I had none over the last 2 years...which is funny, because i fully expected to have them - and put a custom rom on it. There are just two things that irk me...you can't disable IPv6 and the adaptive charging is still not enough for me personally, i would have liked to have a hard limit...
Plenty of OEMs allow bootloader unlocking, stop buying Samsung.
Safetynet issues
It's Google Play Integrity checking now, and as someone who has been using LinageOS on unrooted phones for a while, I've never had these issues. Not to say people out there aren't having them, but it's not as bleak as people seem to believe it is.
I have one phone that's rooted, and I have to use magisk to hide it, and that occasionally has issues, but not the non-rooted ones running custom roms.
It's Google Play Integrity checking now, and as someone who has been using LinageOS on unrooted phones for a while, I've never had these issues. Not to say people out there aren't having them, but it's not as bleak as people seem to believe it is
Maybe a week ago they borked the integrity of custom ROMs. GPay/Wallet doesn't work anymore with Magisk shenanigans. Happened to every ROM I checked.
People used to got to Custom ROMs because OEMs were really doing shit job, that's not the case now given now.
Yep. I used to use custom (ROMs, kernels, etc) for the extra features and playing with my phone like a shiny new toy. Now I use GrapheneOS because OEMs and Google don't do security and privacy anywhere near as good as GOS. And I can live with the minor inconvenience of apps that use Play Integrity API, though I do encourage the app devs to switch to hardware backed attestation because: "Android's hardware attestation API provides a much stronger form of attestation than the Play Integrity API with the ability to whitelist the keys of alternate operating systems. It also avoids an unnecessary dependency on Google Play services and Google's Play Integrity servers." https://grapheneos.org/articles/attestation-compatibility-guide
Now try to use most of Banking applications (even McDonalds app lol)
Most of these application require Google Play Integrity. So practically, you are enforced to use Google Play Services or buy a second device to run android with gapps and then power it off (that's what I did)
Do custom ROMs still have issues with some apps not allowing them? It's been an eternity since I tried one and I don't know if it's a hard requirement, but at least when I did try it, I had (?) to root my device and my bank apps refused to work after that.
Many applications especially banks require Google Safetynet to be functional, even without root. I am running DivestOS, a hardened version of LineageOS without gapps, and I can't have access on my bank because I chose freedom.
Democracy at its finest...