If you get an error like Settings schema 'org.gnome.settings-daemon.plugins.xsettings' does not contain a key named 'antialiasing' Trace/breakpoint trap (core dumped), you are using the GNOME desktop environment with a Wayland compositor. This combination causes issues for the Modrinth App.
To get around this, you need to specify the GDK_BACKEND environment variable to x11. In other words:
$ GDK_BACKEND=x11 ~/path/to/Modrinth-App.AppImage
This issue is being tracked as #941.