I want it to no longer be mandatory that the other has a controller and only I optionally it

[Apprendista]

I tried to use RemotePlay with Team Sonic Racing, me using an XBOX controller and my friend using the keyboard.
He couldn't control anything, as if his keyboard was disabled.
I find it objectionable that two separate keyboards cannot be detected as such, but even if that just isn't possible, I would at least want the remote player without a controller to be able to use his keyboard as if he were using mine.
I have already read a discussion about how to emulate the presence of a controller but neither of the two proposed methods worked, in addition to being terribly complicated.

[Different55]

This is already possible. I've played games where I used a controller and the other person was on keyboard/mouse. It's not possible for you to both use the keyboard and mouse, OS libraries and games just aren't built for that typically. But if the keyboard's shut off for you, that's a problem with the game you're using disabling keyboard input if there's any controller input. Some games do that, but there's nothing Steam can do about that.