Basically I want to keep pressing A and press left arrow key, for example.
I tried with Encoder left/right rotate and Keyboard (arrow and A pressed down).
Somehow I got it to work, but even after finish rotation the conceder, A key is press down and do not get released.
AFAIK in Capture One, pressing the mapped Speed Edit key + Space will reset that parameter to its default value. So just using the same way as above, you can send that to the software easily.
I would also advise you to wrap the Key+Space into a Press/Release block so as to not send the reset twice on each encoder press.