I was using s3, and I added the b2 variables in a "throw everything at the wall and see what sticks" process. not a good idea, but I do try to fix things on my own before posting things here. Occasionally I can figure it out lol. I've removed the b2 variables.
It occurs to me that I have restic set up as an app in backblaze according to this, so I'm not sure how it knows which bucket to use. appending the bucket name to the url does not change the outcome.
Now I am also getting: Fatal: unable to open config file: Stat: 401