I'm not sure. I recommend reaching out to support to find out.

That said, I've been using Backblaze for years on both a laptop and desktop computer. It seems to work fine without needing to manually telling it to backup. I do occasionally tell it to pause an active backup if it's slowing down my internet and I'm on a call, etc. Generally though, it should intelligently choose its upload speed depending on available resources.

The only "downside" of Backblaze, which is true for any online backup solution, is that the initial backup can take a very very long time. Possibly weeks, depending on your upload speed and drive size.

If you use Powernap, I believe it'll still update.

No, it does not.