Well this wasn’t the promise backblaze made a decade ago when we started using their products.

Now I need a new solution that will work for my parents

Of course, I wouldn’t use their client anymore. Actually, I would have never used it from the start as it’s not open source. I think for backups there’s no better guarantee than that. I don’t mean because you could look at the source code, I mean because in my experience open source products tend to care more about their users than not. At least for such foundational tools.

Backblaze Computer Backup != B2 Cloud Storage

You can't connect to their Computer Backup service through third-party software.

When an org quietly degrades one of their products, you should expect this behavior to occur again.

That is a lot more expensive if you have more than a small amount of data.