FileZilla Pro + Backblaze B2
In the very unlikely case that someone hasn't tried and doesn't know:
I know there's Backblaze CLI as well, but FileZilla Pro seems quite easy, straight forward, and immune to any network interruptions. It's nice.
For 20 bucks, you get 5 years of updates, and 3 installations (one-person registration, "if you have more computers, contact us...").
Not an expert, not a pro, not selling it - but I've spent a few days looking for a way to easily upload, and download stuff from B2 storage, and this is what I'm happy with, for my intended use. Idiot friendly.
Mostly harmless ™