It seems that they've figured this out for waynergy https://github.com/r-c-f/waynergy

Keyboard mapping is a bit wonky, and only works as a client but it's a start and let's us keep using barrier on wayland for now.

Ubuntu is rolling out the LTS->LTS upgrade this month, prompting the bulk of its userbase to install 22.04. This time around staying off of Wayland is even more difficult, most people will default to it.
While waynergy works as a client, any Wayland-capable server is needed about now.
A great opportunity for input-leap to distinguish itself from barrier ;)

Just threw $20 at the bounty. Any way to help this further? (my coding time is too limited)
I'll try rkvm again in the next few days, but my previous attempt was unsuccessful.

Wayland support has been merged to InputLeap today in #1594. It still requires custom builds of mutter, libportal, xdg-desktop-portal and xdg-desktop-portal-gnome, so the code is not directly useful to the end users just yet. Thanks a lot to @whot and @ofourdan for making this happen.

Closing this issue as a duplicate of #109.

Ubuntu is rolling out the LTS->LTS upgrade this month, prompting the bulk of its userbase to install 22.04. This time around staying off of Wayland is even more difficult, most people will default to it. While waynergy works as a client, any Wayland-capable server is needed about now. A great opportunity for input-leap to distinguish itself from barrier ;)

Just threw $20 at the bounty. Any way to help this further? (my coding time is too limited) I'll try rkvm again in the next few days, but my previous attempt was unsuccessful.

Where those changes on those components upstreamed at some point ?

There is no reasonable "upstream" any longer (see this discussion). Nobody maintains barrier. From what I could gather, input-leap is the only reasonable chance at an active fork right now.

Of course there's also always Symless, but I wouldn't hold my breath for them to come forward with a solution first.

I am talking about the patches for their respective git repos....

Mutter, etc

Symless have already started talking about libei, but didn't really recognise the efforts that originated with this project. I daresay they'll use libei. This is the nature of open source.

With regards to upstream patches for the components needed, this is a good listing: https://gitlab.freedesktop.org/libinput/libei/-/issues/1