Previously this would be OnePlus, but it looks like their newest phones aren’t rootable. I used to have a Xiaomi phone for this also, are they still good?
Ik you can root smartphones from a lot of brands but I’m looking for one that has good ROM support and doesn’t try all kinds of tricks / to prevent you from unlocking the bootloader
I had a similar question few weeks ago, check it out https://biglemmowski.win/post/267187 (https://lemmy.world/post/7024053)
If you are looking for just easy root and/or good ROM support then Pixels come out on top.