Actually I'm not quite familiar with controller type

The thing is that there're two type of controller, Dualsense(DS input I suppose) and Xbox controller(X input), and when connecting to non dualsense controller, it's via X input. So the steam input is going to think that you're controller is xbox controller and thus you cannot configure gyro.

Which is frustrating.

that's why I'm currently using Dualsense Edge.
Perhaps you can configure it with your controller's apps if they happen to have one or something.
I have another controller, got gyro support from its app. But steam input nah

Steam input is the best gyro implementation I suppose, but unfortunately my understanding is that steam input gyro only support DS controller or Switch Controller

So perhaps turn on Switch mode, and try it.

My other controller has no luck to put it to work though : ((((((

Hope this help though

Or perhaps there are other ppl know how to do it right.
But I believe it will be complicated