Phantoms do not have a mob cap, causing performance issues

I made a world with friends to play minecraft 1.16.2 with. The new release!
We decided to make a world where it's always night using the commands:
/gamerule doDaylightCycle false & /time set midnight
But now phantoms never die and its lagging my game, why do phantoms not have a limit like other mobs?

This is a big issue, we no longer want to play the game since there are so many phantoms. I took photo, we have been playing for a week now. Using tunnels to go from base to base since it's too crazy going outside!

Please fix this!