We have flown out of EWR the past 20 years since it has more nonstop flights to SXM than other airlines in my area. Because the pandemic caused airlines to provide incentives to pilots to retire early, there aret not enough pilots. Next the pandemic caused the flight controllers to retire early and delayed the introduction of a new computer system for flight control. All of this added to current delays/ cancellations at EWR. United is reducing the number of flights out of EWR to avoid cancellations. I used to be able to fly nonstop to SXM on some week days in low season not this year only nonstop is on the weekend in September.
All of these things produce the current situation.

Things should start to smooth out by mid year hopefully.