I recall encountering this when I first did my upgrade from 3.x to 5.x. If you really want to roll back, you have to go two snapshots back.
There may be more information in one of the old migration threads here:
If you have any comfort with the command line, I would recommend getting a little familiar with schnapps. You may be able to get back to your working 3.11.23 install and re-try from there.