Is Backblaze Suitable for Production?

Backblaze is great on paper. I need to decide if I should use it for production. My main concerns:

1) Downtime every Thursday from 2-3pm: Does this affect normal B2 operations like upload/download/delete objects? This would be a major show-stopper. From the official page, it seems only a select few operations, like creating/deleting buckets are affected, which is fine. See https://help.backblaze.com/hc/en-us/articles/227807447-Backblaze-Maintenance-Schedule

2) Limit size when using client-side signed url: B2 does not allow this. Basically, you get a link that can upload any sized file to a bucket. A malicious user could upload a 5gb video file, for example. S3 and others do allow setting a limit. The obvious solution to this is to use your own server as a proxy. But this means slower uploads, and the extra cost of server bandwidth/cpu.

Any other insights much appreciated.

Thanks!