It might. You might have trimmed off quite a few versions. You can see if home page Versions shrank.
It depends on things like download and upload speeds (are you bandwidth-limited?), CPU and disk, etc.
I also think (I tried looking once) that the wasted space number is an overall amount that triggers things.
Some dblock files might have very little wasted space, and these aren’t compacted. Worst case time would be to download, repackage, and reupload everything, but you’re not quite there. Maybe you could assume you were and start with that to ballpark time, as you won’t get the full speeds an Internet speed tester may show, because they run lots of threads in parallel. The compact operation is not parallelized.
Duplicati Profiling level logs show actual DownloadSpeed and UploadSpeed if you want to look at them. Smaller files go slower (but they’re small…), so transfer time is probably dominated by big dblock files.
But none of this should cause anything to stop. It should just do lots of download-upload, deletes cycles.