Hey @Toshio_Kushiro, and welcome to the community!
Only one TIDAL account can be linked to Roon at a time, so only one of the family plan accounts can be accessed by all Roon profiles.
If you’re looking for each Roon profile to have their own TIDAL account, unfortunately that is not possible currently. I do recommend that you add your voice to this feature request here for allowing individual Roon profiles to access individual TIDAL accounts.