Yeah, I've tried a bunch of backup services, and they all have issues with this kind of file count :/

I tried using Backblaze about a month ago, but it simply couldn't handle my backup needs (3.3 mil files, 600 GB) - it had issues like high memory usage (above 6 GB), couldn't figure out how many files there are to backup, etc.

Do you have any information if this new client (5.0) is any better for my needs?
And you probably still can't select specific folders/files to backup, it wants to backup whole hard drives?