Prisoner’s
That is not how Elo’s math works ( see link )
The short explanation is at least one player will set an awesome 5* defense team. To get to 2970 trophies, assuming Devs did not muck with that part of matchmaking, you will have to defeat it multiple times. But each win will eventually give you +1 trophies and each loss -50 trophies.
Notes
Links
( [Primer] Basic explanation of Trophies or Where do Trophies come from and why do I lose them? )
(What is the highest score ever achieved - is it still viable today? - #57 by Gryphonknight)