I have been on several cruises with different cruise lines. They all have had pretty spotty wifi, particularly in the staterooms because of the metal in the doors and walls. The signal strength can fluctuate wildly and there are usually all sorts of dead spots in the staterooms.

If I needed to work on a cruise like it sounds like you need to, I would make sure that there is a place onboard where I could reliably work in one of the public areas like a library or a business center or something like that. The wifi should be more reliable there than it would be in your stateroom. You may have to scope out multiple spots in case one gets overrun with rowdy passengers.

I don't have experience with starlink, but my guess is that it would need a clear view of the sky for a connection, which would mean being on-deck somewhere or possibly a room with a balcony could work.