There exists no (or very few) subscription service that has no tier without advertisements. You are panicking for no reason.
Netflix?
Hulu?
Youtube?
Spotify?
Adobe?
Duolingo?
X?
This is simply not (always) true. Spotify injects ads for Podcasts even for paying users. YouTube has tons of videos with adds built-in by content creators.
Then everything is ok since everyone's doing it!