I have worked onboard both round the med and a transatlantic.
I think Infinity is an older ship and may not yet have Starlink, I was on the Silhouette without Starlink during transatlantic and while in the Med section Teams calls were okay.
On the Beyond things were better, coding was fine and Teams calls okay. This was with Starlink in place.
What I would say though is the latency is pretty bad. Two way conversations on both ships were difficult due to lag.
In a lecture where it's more broadcast it should be better.