I have wanted to migrate to using Proton Drive for some time, but each time I experimented with it I ran into bugs/slow speeds. However, I am happy to report that with the latest updates described in the link below that it is massively improved and nearly as fast as my experience with iCloud ADP.
For real world experience I was able to upload all my data I wanted (around 100GB) by just setting it up overnight and by the morning everything was there. This includes >15,000 photos uploaded directly from my iPhone. I have now fully moved to Proton Drive and cancelled my iCloud+ subscription.
If you have been similarly interested in migrating to Proton Drive but disappointed with experiences in the past, it may be worth giving it another look with their recent updates.
Edited: I ran into some issues with ProtonDrive and have moved back to the walled garden. See post below for details if interested.
Yes. In MacOS you can open the drive folder and just copy/paste as much as you want simultaneously. On iOS if you hold down on a folder it allows the option to “select all” and a download bottom appears on the bottom right of the app.
Out of curiosity what is not working for you?
For my use case it has been flawless, but I use it mainly as backup storage and as a ‘sync’ function which may be more complex with more potential places to go wrong.