I just tried Ubuntu OS Desktop arm processor version.
Installed it to SD card.
Booted on a Raspberry Pi 400
I thought I was using my Android based phone.
A lot of stuff seemed the same as it is on my phone.
This thing was about 8GB in size, after it completed the install.
Fast, it was not!
Everything you tried to run, took 5 to 10 seconds to start, and open up in a window.
Any of the Puppy versions for a Raspberry Pi, work fast, as they do on a regular x86 computer.
Same SD card install.