I wrote that weeks ago.
I found a solution.
1. Connect Ekos to the Raspberry HQ Cam
2. just set the exposure to higher 10 sec, maybe 20sec
3. Set the gain
Now you can play with the settings and they will be applied.
If I set the gain before exposure, they will all be ignored.
for everyone who has problems with the speed of Firecapture in Stellarmate.
Here is my solution:
sudo nano /boot/config.txt
change "dtoverlay = vc4-fkms-v3d"
# dtoverlay = vc4-fkms-v3d
3D support is deactivated and the system works with the old (native) driver. This relieves the system and allows Firecapture to run faster.