

Plex runs relay servers where your Plex server will connect to the relay and your player will also connect to the relay, making both ends of the connection egress type as far as routing and access control goes. https://support.plex.tv/articles/216766168-accessing-a-server-through-relay/
It’s optional and likely not everyone uses it, but this provides a way for Plex to do remote streaming without the Plex server being reachable directly from the internet.
Separately, it costs money for Plex to run.
I’m in the same shoes about new job having to use teams and I wildly disagree. It is awful.
The best part of it is the noise cancellation on the microphone in calls seem pretty good and having a chat created for meetings is a good integration. BUT…
Compared to zoom, I guess it’s not a big deal really. I’d prefer zoom but it’s oh well. Compared to slack (which has it’s own set of problems, but still) however it seems like a pile of shit in my opinion.