Dropbox preventing other backup software from working

Apologies if I'm in the wrong category, and I'm also a new Dropbox user. My problem is that my Dropbox installation has stopped my other backup packages from working correctly. I prefer to have multiple approaches to backup going in parallel. I used to use ACRONIS Cyber Protect and Norton 360 writing to remote local drives, with both run manually (no scheduling). I acquired a Dropbox licence and have the backup feature running on three Win 11 PCs. However, it became obvious that once Dropbox was active, the other packages were not working correctly. In the case of ACRONIS a full image backup used to take ~60 minutes and produce a validated backup of ~400GB. After installing Dropbox, ACRONIS completed in 2-3 minutes and produced a backup folder of a few 100MB. Clearly something is wrong. Dropbox helpline could not explain this but simply said that competing backup software is not a good idea on a machine and, in any case, why would you? My answer to this is that just relying on Dropbox is not really 100% safe. What I am looking for is a possible fix that will get at least ACRONIS running again (a more professional package than Norton 360 Backup). I have asked ACRONIS for help and they are looking into it. All I have found is that there can be problems if OneDrive is used (not) alongside Dropbox.