This might help. It should give you a good idea of how busy the airport will be. I'd check departures 1 hour before and 1 hour after your flight is scheduled to depart. The more planes in that two hour window means the busier the airport. Airline have always said be at the airport 3 hours before departure. Having said that, we have on occasion been on time only to find no one at the checking in counter. If it was me, I'd get there early, check-in and then go sit at The Groovy Grouper or go upstairs and have some lunch at Margaritaville. I like The Groovy Grouper thing because you can check the security line every once in a while to see how busy that is. Also you can make a game at the airport exit door. See how fast it takes people to shed the fleece jacket or get the knee high leather boots off.
https://www.mbjairport.com/flight-information
I have been traveling to Jamaica for over 40 years and have never arrived at the airport any earlier than 2 hours before departure. Never had any problems. Usually thru the check-in in less than 20 minutes at most.
I flew back last Tuesday and I have never seen the airport so packed. I think this was due to the inability for most people to be able to check in online in advance. Almost everyone I talked to there had to wait forever to get to a kiosk due to this. I waited almost 2 hours to get to Delta's kiosk then another 30 minutes to check the bag. You can use any kiosk to get your boarding passes so if you see a one available at another airline, grab it. There were too many people when I was there so there were no free kiosks. The security line was very long at times. Thank god I had Club Mobay and used their line for security which took 2-3 minutes. 3 hours is the least you should get there to be safe. I showed up at about noon. It did lighten up at about 2:00 that day.
I have been in the Airport 3 times since August . I have departed on a Sunday in August , I arrived 3 hours early and the plane was boarding when I finally got through. The security line was across the airport . The last two times i had club mo bay which helped . In Dec I flew out on a Tuesday and once again airport was packed. In Feb the airport was least packed but still took over an hour to get checked in. Enjoy your days in the sun .
We are leaving today.. arrived at 8:30am for 11am flight. No lines. 4 people in security area. Empty. Very odd.
We were scheduled to leave yesterday and made it home via Delta after a several hour delay. The rest of our family were flying American and were on the plane for about 45 minutes then the flight was cancelled until today due to not having a legal flight crew. They got to the airport 3 1/2 hours early today for the rescheduled flight after sleeping 5 in a room at the only hotel that they could get - at a cost of 888 US dollars. They tell me that it was horrendous this morning with all of the rescheduled flights and it took them the entire 3 hours to re-check in and get through security. They are currently on board the plane again and hoping that it actually gets them home this time! And beside sharing this story - I guess the point is that you just can't predict what you will find at any airport these days - it is definitely not back to pre-pandemic conditions.
How could it possibly take that long from the airport to negril? Sounds like there's a story there.