If you absolutely want it that night and don't want to wait up, I would say pick it up yourself. If you are okay with them holding it overnight, I would wait until you are ready to go to bed, and then if it has not yet arrived, I would go down to bell services to ask them to just hold it overnight. Actually, we discovered if it gets to the resort really late, they will hold it without you asking even if you are sitting there waiting for it.
We typically arrive before 5 and have never had an issue getting our luggage within the 3 hour window with arrivals at 5 or earlier; however, night time arrivals are a whole different matter.
This happened in 2017, but I still have not forgotten it. Our flight got in between 7 and 7:30. We were staying at YC. At 11:00 p.m. we still had not gotten our luggage, so we went down to the front desk. We were told that when people come in on evening flights if there are not that many people coming in to that specific resort that evening, they hold the luggage until the last flight eligible for ME luggage service that has people coming to that resort arrives (usually 10:00 p.m.). We were told they do that so they do not have to make multiple trips to a specific resort for just a few pieces of luggage. We were told that we could expect our luggage to arrive around 12:30 or 1:00 a.m. They would not have brought it to our room that late and we would just have gotten it the next morning had we not advised we wanted it as soon as it arrived. DH went downstairs when it had not arrived by 12:40 to check on it and stayed down there until it arrived (just before 1:00) and had them give it to him downstairs and he brought it up himself- so we wouldn't have to wait for bell services or have them coming to the room door that late. We have never had an issue with ME luggage delivery before and we were never warned that was a possibility for an evening flight. The CM at the front desk made it sound like this was a VERY common occurrence and that if your flight arrived at 7:00 p.m. or later on a low or moderate crowd WDW time, that it would be pretty expected.
.