First off, thanks for this very nice tool! I had a problem with remapped keys and thought that others might want to know about this. In short: Microsoft PowerToys doesn't seem to work with ID but switching keys with the registry seems to work. (At least if both/all systems switch them the same way.)
I have an older Win10 system where I switched LeftCtrl and CapsLock through the registry (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout\Scancode Map). I also have a newer Win11 system where I used Microsoft PowerToys to switch these keys.
This didn't work with ID, in neither direction. It didn't switch the keys on the remote system.
Then I figured the problem might be the different mechanisms and switched both systems to using PowerToys. (It's more convenient than the registry method in that it doesn't need a restart.) It behaved differently -- now it did switch the keys on the remote system, but on the control system (while the focus was on the remote system), it still toggled CapsLock when hitting the CapsLock key (even though it worked correctly when the focus was back on the control system). With this CapsLock toggling on the controlling system, something like LeftCtrl-V on the remote system worked only every other keypress.
Then I abandoned PowerToys and used the registry method on both systems, and now it works. I'm sure there is a proper explanation when diving into what mechanism PowerToys uses, but for me, this is good enough. (It would be nice if the PowerToys method was supported by ID, but as long as there is a work-around...)