Hi,

Which decent phone that will last me for some time and wont break easily is the best to buy that lets you fully unlock the bootloader so I can flash custom ROM on it and root it if I wanted to by for example using Magisk by flashing patched boot.img and (optionally if specific model allows) installing custom recovery?

I have a Samsung that I could unlock bootloader on, however Samsung decided to block the option to unlock OEM starting in One UI 8.0 on all regions, and I was unlucky enough to update my phone (because I didnt know) so I cant root/flash custom ROM on it.

My guess would be some Google Pixel model,? but which one should I buy that has support for most ROMs and TWRP?

Google is also soon introducing mandatory
ID verification for developers that want to publish their apps on Play Store on all Andro id verified devices, whch is another reason I want a phone that I can flash custom ROM on and root.

Also where should I buy new phone from? I think I should avoid buying from carrier and instead buying it online or from local electronics store?

LineageOS (a custom Android OS) has list of all phones which it supports. Since you can't install custom OS without unlocking bootloader, you can consider this as list of phones with unlockable bootloader

https://download.lineageos.org/devices/

My personal opinion is that custom android Roms are going to die slowly after google locks down android.

If you're open to it, you might want to look into Linux phones. Specifically Fairphone 6 with PostMarketOS. It's not quite there, but it's close and they are actively working on the last couple hardware issues. Sounds like it should be ready within a month or so.

This thread talks more about it:

https://threadiverse.link/piefed.zip/comment/6553012

I actually never thought of using lineageOS support list like that. Thanks