Avalonia does not have a Wayland backend now, but they say it's a priority: https://avaloniaui.net/blog/bringing-wayland-support-to-aval...
I'm sure there's a better place to track the progress on that.
If I remember correctly, it's a priority for like 5 years or so.
You can (and could have for a while now) just use Avalonia natively. It supports Windows/Mac/Linux/WASM natively already. I think this work is primarily for those who already have MAUI apps and want to target Linux/WASM from an existing codebase.
I'm wondering why all the demos of modern UI toolkits look and feel worse than Delphi 1 demos from prehistoric age.