So, after all of this:
- redownloaded the blockchain without prune
- opened the wallet X1.dat ...
- the wallet opened after an hour of whatever it was doing in the backgrond (it's 2020, can't believe the bitcoin core software is still this kind of thing, but ok... we'll have to deal with that)
- the wallet opened, but there was nothing, no transactions, not adresses, nothing (I'm sure there must at least be 10 tx in there)
- re opening the file with the -rescan option in command line now. It's not giving a status just "rescanning" on the first page.
So yeah. No smooth sailing for bitocin core (Now I rememeber why I didn't use this too many times

it's not exactly user friendly to put it mildly).
If the currect one opens somewhere within the coming 24h I'll maybe know more.
Is it true that Legacy wallet transactions aren't shown in there?