you have to upgrade step by step through all major versions as stated in the official guide:
It is only possible to upgrade one major version at a time. For example, if you want to upgrade from version 14 to 16, you will have to upgrade from version 14 to 15, then from 15 to 16.
you could try to revert you old version
but please beware or downgrades it could brake your system!
WHY? I summarize: you tried 3 unsupported operations for no reason (web updater and 2 downgrades) but didn’t collect the logs as I recommended? maybe this forum is not the right place to help you…