You can indirectly subscribe to Paramount+, Lionsgate+, and Discovery+ through Amazon Prime Video so those three aren’t so much of a problem.n
The three main glaring omissions are YouTube, Apple TV+, and Disney+, in my opinion.
Maybe it’s more to do with BT TV still being tied up with the YouView platform, which I think has basically been superseded by Freeview Play and Android / Google TV on most TV’s and STB’s these days.
I did take the free 7 day trial of Paramount+ not long after it started but soon canceled. As at time was not enough on there worth watching.
Out of the pay TV serivces that I have, Prime, Netfix, Disney+ and Now(Now TV). Disney+ is the one I use the most.
I use the Amazon Firestick more for apps then the Youview box.
As of over a year ago. I no longer have BT TV and just under two weeks ago moved from BT to Sky for my FTTC on a similar package that I was with BT. After being with BT for everything for well over 20 years and ever longer for landline.