All three main desktop operating systems suck for very different reasons

Or if you prefer Chromium, Kiwi Browser allows extensions

The ReVanced url you gave is an impersonator, real one is https://revanced.app

edit: SmartTubeNext one most likely is too, doubt it has an actual website so just link to the repo https://github.com/yuliskov/SmartTubeNext

That’s completely different. Divolt runs Revolt, which is self-hostable but not federated (aka what happens on your instance stays only on your instance)

No. While it is in theory possible if you sign the image, it’s not worth the risk. If you relock the bootloader on a Xiaomi device and the image isn’t signed (and it most likely wont be) the phone is done for. Relocking gives basically no advantages that can’t be fixed through a root module.