Here is what my website looks like.
Discussion
That's not a custom domain
If you DM nostr:npub1xdtducdnjerex88gkg2qk2atsdlqsyxqaag4h05jmcpyspqt30wscmntxy I think he can set you up with one if you use npub.pro He wanted to test it out.
Can’t you just CNAME to that?
only if npub.prob supports it
We do now. There's Custom domain section in settings, released to public access as you are asking. You can also self host on GitHub https://blog.npub.pro/post/how-to-self-host-on-github/
So you could just add a custom CNAME and have your own domain