Now I have found a mystery behaviour on my new Pixel 9 Pro XL only:
For about a week now, I have deliberately deactivated battery usage in the background in the Obtainium app.
And I also switched off ‘Mobile data usage’.
This way, Obtainium consumes much less energy (it is enough to check for updates after starting the app manually).
But on my new Pixel 9 Pro XL this doesn't work anymore!
After switching the background usage to “off” and waiting a few seconds, checking thereafter the switch:
then the switch is “on” again!
This behaviour I can see only on the newest Pixel, not on my Pixel 7 Pro or 8 Pro models.
Maybe it isn't an issue of GOS for Pixel 9 series, but I am unsure…