FWIW some of the Plasma Mobile apps are available as Android apps, but I my experience most of them are not really stable enough for daily usage.

If you are looking to run the whole Plasma Mobile stack, you could use Termux and proot to run it “natively”, although I imagine it would likely be a huge pain to get anything working reliabilly, if at all.

btop is not Bazzite specific, it’s just preinstalled on Bazzite. You can install it on pretty much any distro.

It’s not just mimicking Linux tho. It’s running an RISC-V emulator via an DLL that is capable of running a (more or less) full-fledged Linux image.