I feel like the sole reason jellyfin exists is because some people don't want to fork over the cash for lifetime plex. Plex just works. Jellyfin is constantly in a state of failure or bad state.
They violated their promises. They stated that they didn't track or know what people watched. This is absolutely a lie. They have to track it to email it out to friends.
I deleted my account, destroying my lifetime plex pass and moved to Jellyfin. Yes, it's not as polished, but it preserves my privacy and I don't get ads filled free crap tv shoved in my face all the time. Plus Jellyfin generally does just work. I don't miss Plex at all.
Regardless, the polish isn't enough to justify a company that has modified the deal (we don't track what you do). Once that first promise is broken, the trust is broken forever.