Libadwaita is only compatible with gnome and only works with gnome. Other DE’s can try to make it work in their DE, but the experience for them is hostile.
To put it mildly, gnome devs are being dicks about it as much as they can be, because they consider themselves the only “real” desktop environment to Linux.
If you want your apps to be cross platform, you can just use gtk3/gtk4 instead, or any other ui library. Even QT.
I use gnome ATM because I think paperwm is the best desktop experience on any OS, but the gnome DE devs are just assholes and they break my heart.