I want to backup multiple external hard-drives that have photos from a range of old phones. I can't do this on the desktop app, it looks like https://protonmail.uservoice.com/forums/932839-proton-drive/suggestions/49195883-photo-desktop would need to be done first.
Looking at the web UI, I can't select a folder. I would need to select all the files, which adds friction when I have multiple drives to back up.

Here's some extra requirements in an approximate BDD format.

Kicking off the process

When I plug in a SD card or a USB drive
Then I get an autorun prompt to back up the photos on the drive

Given I've plugged in a SD card or a USB drive
When I open the Proton Drive app
Then I see an external devices section (accessible from the navigation panel) with a photo backup button for each drive or SD card

Can choose what to back up

When I choose a drive to back up
Then I can view a file tree of the drive
And I can select all, one or multiple folders and files to back up

When I confirm my photo selection
Then I can chose a photo folder to save them in

Given I have duplicate images
When these are identified by comparing hashes of the file content
Then I get a option to delete one or more duplicates

Making the process robust

Given I have a lot of photos to back up
and potentially disruptive power savings
When I start the backup
Then I am prompted to turn off these settings

Given a backup has been disrupted (WIFI issues, computer hibernating, power cut etc)
When the issue has been resolved
Then the backup will resume

Making the process efficient

Given I have multiple drives connected
When I have started one backup
Then I can back up additional drives
And this will run concurrently or consecutively based on the system resources

Given external hard drives can be larger than the systems drives
When the backup is happening
Files will not be saved to the local Proton drive folder