Damn, sorry that didn’t help.
Please note that I’m only guessing and definitely don’t want to give you anymore advice that doesnt work!!
I would think that you could still rollback to v18 https://github.com/lzxindustries/firmware/tree/master/memorypalace. The user guide on here has instructions on updating firmware when it doesnt boot. Memory Palace User Guide I found removing the SD quite unpleasant so hopefully you don’t end up having to do that.