The remote input issue is related to Wayland, and currently all wlroots based compositors (including Hyperland) have issues with this. KDE Plasma has merged support for remote input to work with KDE Connect, however many other DEs do not have the support merged, and will have to rely on xdg-desktop-portal-wlr to implement it. Here are the related bug reports and issues:

https://bugs.kde.org/show_bug.cgi?id=448604

https://github.com/emersion/xdg-desktop-portal-wlr/issues/2

https://github.com/hyprwm/Hyprland/issues/1775

Also, it seems the other issue is unrelated, are you seeing an error on the command line, or is there a dialog popup, and can you quote what is said? I’m having trouble finding any related issues anywhere on GitHub, even the Hyperland issues around remote desktop did not seem to have this particular error (or didn’t mention it at least).