Hi Achim.
No not with zram active. I had it with magicearth earlier, but i did not see this for a long time now…
I don’t think the cwa does a lot, most of background processing happens in the Google part (or microg if using the f-droid version).
I think that systemui is a los (resp android (thing, not gapps, for the rest that’s way over my head 