eCloud data usage / "overdrive"

I know there are already a few threads on this (e.g. this and this ), but as they are marked as resolved and closed, I want to start a new one.

On a regular basis (every couple of days), the ecloud goes into overdrive and suddenly uses a lot of data (>500MB) without discernible reason (no photos or video taken, regular WIFI connection, no active app use). This happened on the pre 1.0 OS on FP3, but even now on /e/OS1.0-20220526188859 (after a fresh install, without changing any of the default settings) I get the same issue. I tried disabling background and mobile data, but no effect. It says foreground, but I have never opened the app since I reinstalled the OS.

The only method I found to mitigate somewhat is to set a rather low data limit, such that it turns off automatically, soon after going into overdrive.But that means I need to manually adjust the data limit all the time.

My gut-feeling is, that is starts sync on WIFI, and if I leave the WIFI while it is sync’ing it just continues on mobile, but I have no data to back that up.

I hope someone can help, this is getting a bit problematic.
Cheers,
René