There might be some help eventually if this feature request gets implemented:
Idea for restoring to download inspired that, and it might be more feasible now thanks to recent Duplicati Console work, but it’s unclear issue matches forum, which sought download over Internet. Issue might just be a local convenience.
Having backup file data near Duplicati servers adds security/privacy concerns, however even mere download to a browser could let you use remote browser, provided you can get to your PC – and there are lots of services to help do so.
Some of those tools can transfer files, so maybe that’s an alternative – run live.
Blog post: Cut restore times by 3.8x - A deep dive into our new restore flow
is a good technical description of what it takes to restore – not an easy process.
Prior requests said this too. OTOH a high-end phone is likely faster than my PC.
Restoring encrypted files from backup to an iPhone
Viewing backup saved on Dropbox from Android
Other option besides remote browser or remote desktop type tools might be VPN. Punching a hole in router firewall for FTPS or SSH might also give access to file.
All of those have the drawback of needing PC on. For an off PC, third-party sync somewhere such as Google Drive or better might allow access through that login.
Involving any other service also adds security/privacy issues, so there’s a tradeoff.
Duplicati does not do well even as a sync tool, for reasons you mentioned such as potential of going in for “direct restore” in the middle of remote backup. It might fail, even at the potentially slow DB recreate step. I suppose one could rclone/sync DB.
Restore shouldn’t harm the destination files, and the DB on remote PC is also safe.
Setting this up yourself is some work, but I’m doubtful simple solution exists except going into the running PC with some available tool to grab the latest version of files.