Sorry to hear about your loss.
This is my opinion and not legal advice. I have been an executor before myself.
To close the estate, the executor will need to settle all debts even if nobody accepts the timeshare (nobody has to accept property they don't want).
But i agree, this one has some value and you should be able to minimize the impact. So it seems to me you are (the estate is) going to have to pay the 2025 MFs anyway since they will be due soon.
The unit had more value a few years ago before all of the hurricanes in FL and reserves having to be increased, and the estimate from jwalk03 sounds reasonable - which is close to the MF owed. You can try to sell it and ask for MFs to be covered. Or you can try and take the path of least resistance and give it away here on TUG and ask for the MF to be reimbursed and the closing costs covered. If nobody takes it after a few months, then back off on the reimbursements - but being a lockoff that is a known great Marriott trader in Interval, I believe some Tugger will be glad to take it off of your hands. The "buyer" should be able to get some use out of it in later in 2025, even if they put it into Interval.
There is a closing company named LT transfers that is pretty reasonable (around $400?). Do some searches and see what others say - you should find plenty of hits. Using a reputable closing company should minimize the risks on both sides.
You will get more feedback also if you post in the Marriott subforum.