There’s nothing you can do to stop Plex collecting the data, but you can at least stop your friends seeing what you’re watching by adjusting the privacy settings.

Before the move to Apple Silicon this could have been put down to Apple’s intransigence (although you could still upgrade the SSD on the Intel Macbooks), but with the additional integration of the M1 and now M2 and M3 then it’s the way it has to be in order to pull off what it does.