Have you perhaps tried removing the in-built music service from within the Sonos App and then adding it back again via "Settings/Services & Voice”?
OK think I got it. I need to add the category rather than any album. Just added Favourite Playlists in Tidal. Now it shows in My Sonos under heading “Other” as “Favourite Playlists From Tidal”. Can’t seem to rename “Other” to “Tidal”.
There was a time when this worked. The “My Sonos” home screen showed Tidal Playlists properly. They could be selected and played.
That was at least a year ago.
I no longer use Tidal but have the same playlists over Spotify, Amazon Music and Apple Music.
For the respective Playlist to appear under My Sonos > Playlists, I believe you have to manually add each one. They don’t appear there automatically, or at least they never have for me in the past.
Therefore, if you go to Browse → Tidal → My Collection, until you can view the tracks in a particular Playlist, then click on the “…” in top right, there should be an option “Add Playlist to My Sonos”. Once you’ve done that, that Playlist will appear on My Sonos tab under Playlists.
If that still doesn’t work then maybe the previous Tidal error still exists today, unless another Tidal user can confirm My Sonos Playlists appear for them.