I can fill you in on what's happened the last three days in a PM before I head off to bed if you want.
I think I've managed to catch myself up by looking over the shut thread but thanks for the offer
All of them until Spider-Man: Homecoming
I tried to watch the TV shows but there's so many of them...
I'll give you a quick rundown of what's left.
Movies you need to watch to fully understand the Avengers finale doulogy: Thor Ragnarok, Ant-Man and the Wasp (after you see Infinity War, before endgame)
Black Panther is a great movie and worth watching but not essential if Infinity War and Endgame is your goal.
Captain Marvel is alright (Iron Man 3 and Thor 2 levels of enjoyable IMO) but all you need to know for Endgame is that Captain Marvel is a thing.
As for shows, none of them really affect the movies with the exception of something from Agent Carter. There is one bit in the second season that ties into Age of Ultron but for the most part the shows just react to the MCU.