Welcome to the forum @ChrisC
Not me (to get that out of the way first).
Best solution for back ups from Mac to Synology NAS to Cloud, and Searchable and Partial and or Full Restores from Cloud? looks like the same question asked to a wider audience, and getting some input.
Duplicati’s pro and con of having a local database means maybe it’s easier to search (but I can’t say for sure that Arq can’t, since I don’t run it, or Time Machine, or NAS, or minion). Which minion is that BTW?
The archive point at Reddit reminds me of something that I say occasionally. Duplicati is not an archiver intended to archive-and-delete. Its search ability is rather crude, and it’s beta, so don’t delete originals… Your response sounds like you have another archive plan though. I just wanted to get a Duplicati point in.
To its credit, it uses the same backup format on all destinations (probably not alone there), which means restoring massive amounts of data over a slow Internet connection has a way out, if shipping is possible.
Sync or some other sort of off-site copy on backup is also possible, but ensuring the timing is right might be tricky. Sync schemes propagate flaws in backups. Independent backups or backup program is safest.
Your wish for a low-impact solution reminds me of tunings people sometimes do to Duplicati to keep the computer running well for its primary work (or to keep fan noise down). Other people prefer backups fast.
One program whose purpose is low impact backups of everything in sight for novice users is Backblaze. Duplicati users (and probably you) may want more control, so use Backblaze B2, but client also exists…
Restore By Mail describes that, and possibly there are raw-cloud-storage services that offer this as well. Internet backups are great, but full restores on disaster can be slow. Duplicati also has a DB to rebuild…
I’m also not clear on when you’d like the backup, and to where. I don’t know why cloud is terribly different.
Restoring files from a backup describes how to pick a point in time for a set of files to restore, or search.
An ideal solution to one person might be way too much work for another. I think tradeoffs are inevitable…