*Update*
GOG support said:
GOG GALAXY does not support PS5 controllers. Additionally, currently there are no official Windows drivers for DualSense.
We suggest here to try using DS4Windows which also offers support for DualSense.
GitHub Ryochan7 / DS4 Windows
Download Version 2.2.1
Seems like there's no other way than using emulating software, unfortunately.
Here are my settings after some rough testing:
DS4windows
I highly recommend to map L3 (left stick button) to one of the other buttons or bumpers on the controller. It's really exhausting to press down the stick while moving and it's not healthy for the stick's deadzone.
stick range (same for RS)
Ingame Controller Settings
(the second Turning Delay which can't be seen on this picture is set to zero, too.)
Some things I've noticed:
Sometimes the ingame settings won't save correctly when leaving the settings menu. After you made your adjustments, go back into the game, then go back to the control settings without changing anything and then go back into the game again.
I also noticed that the Ramp-up Time has influence on the sensitivity. I think Turning Bonus of 1.5 and Ramp-up Time of 0.5 is a good starting point.
The game ads a pretty drastic deadzone (feels like 0.10 to me) when emulating an Xbox 360 controller, even when the ingame deadzone and the DS4windows deadzone is set to zero (0.00).
The Input lag didn't feel great when compared to keyboard and mouse, so I've overclock the polling rate of the DualSense to 1000Hz with this
Russian overclocking software for USB mice. I didn't measure the latency yet, but so far it feels better and it didn't damage the controller.
Greetings