Failing with the same error in 5.0 is strange, I haven't seen such a thing :-(
Apart from reinstalling from scratch, I can only suggest as alternatives:
- further investigation why LVM is not working. However I have no idea what specifically to look for.
- converting without LVM. E.g. you could convert only root and boot volumes w/o LVM, then set it up, create the other volumes, and copy the data.
Regards