Is it possible to self host this and isolate it on your own p2p network? Would be really cool to handle the decentralized part on my own computers without needing to hook into the global p2p.
That's absolutely possible. Everyone is empowered and encouraged to run their own seed nodes. Which would allow you to have an isolated network. Check the docs to find out how to run your own: https://docs.radicle.xyz/docs/using-radicle/running-a-seed-n...