My realm has become completely unusable. I am unable to replace, reset, or open my realm.
All three options run for a little while, and then fail, even with repeated attempts.

I have been replacing/resetting several times today, as I've been trying to get a world with behavior pack uploaded (that'll be a separate ticket). After one such attempt additional replace attempts failed. I reset my realm once successfully, but now can no longer do that either.

Downloading is still working as of now.