Syncing never stops and makes CPU load very high

Hello
Today, I had this “two different accounts access to this instance”+“delete unuseful sync_db files” problem. After deleting, my Linux/Ubuntu 22.04 client (AppImage or DPKG: same result) never stops syncing, making my CPU load very high.

Is there something I missed that could cause this problem?
Merci!

I’ve to say that, maybe, there’s no link between deleting that file and my problem.
Is there a way to “refresh the local db”?