I want to use one computer for backup from multiple network folders.
And through it, make backup to the cloud storage.
Will there be any problems with this backup method?
Use Web Windows version.
There won’t be any issues from duplicacy perspective. You can create a single folder and put symlinks there pointing to all the other folders.
Depending on how you run the duplicacy (under admin? standard user?) there could be issues with credentials accessing the remote folders, but that is not unique to duplicacy.