And you un-installed the previous version before you installed the new one?
(This is only ncessary if you go from 32 to 64 bits or the other way round).
So: if you had the 32-bit version,
then install the 64-bit version.
If you had not done that,
un-install the 64-bit version,
install the 32-bit version,
un-install the 32-bit version to get rid of all traces in the 32-bit world,
finally install the 64-bit version and also restore the backup-ed configuration.
No nothing special.
In the meantime I had to reinstall Windows 11 from scratch and everything is working correctly now.
I guess that there were some system components that were wrongly registered but this is strange that it is so complex to be able to find how to make the right click new context menu working again.
It looks like an equivalent of regsvr32 for the new context menu would be greatly appreciated....