Try https://soundiiz.com/ and import in Qobuz your artists, albums and playlists from Tidal.
Check your Qobuz account (you can use the web app for that) to see how it looks (it is very possible to miss some data since content between Tidal and Qobuz is not the same)
Make sure you have an working roon backup (backup at least two times in two different locations even if they are on the same disk in different folders, and hope that at least one backup wont be corrupted).
Set your Qobuz account in roon and wait for roon to synchronize with your Qobuz account.
See the results (and manually deal with the inevitable mess).
I don’t believe that an artist/song/album from Tidal set as favorites in Roon will keep that status when switching to Qobuz, so you’ll have to deal with that manually (the export function my help, i don’t know)