if you are not used to dealing with bleeding edge shit and fixing tools as they break then please do not attempt to use any of these at least for right now unless it's in a VM

will reply later with something that's much more comprehensive but for now:

redoxos - rust-based, still experimental but very impressive features, i tried it in a vm a little while ago and i was surprised by how well many linux applications worked on it lol.

genode (sculpt os) - this is actually what im running right now its fucking awesome, compartmented OS that uses seL4 as its microkernel. commonly used in research/academic environments. most games i've played can work if you are willing to spend an unreasonable amount of time troubleshooting.

lionsos - i actually don't really understand how it works however similar to genode it is seL4 based, i think it's supposed to be used with embedded systems?

anyway im gonna go play viva pinata check these out if you want

also look into XTS-400 its super cool but you arent going to be able to access it unless you're a militarynigger

CollapseOS and DuskOS are also interesting. They are implementations of an Forth OS with a bunch of tools added on top. The developer of them says he writes them to preserve computing after a supply chain collapse, however, I think they are worthwhile projects even if you don't believe in doomsday scenarios. It has assemblers/disassemblers for a bunch of architectures, a text editor, a C-alike compiler, and much more. Even if you cannot use them as a daily driver, obviously, they're good in their own right, and worth looking into.

sculptOS
https://genode.org/download/sculpt
https://genodians.org/