Obvious but still good advice: ignore the TV shows. They split off from the rest of the MCU around Winter Soldier anyway, and were not that impressive IMO. If I were you, I'd at least get through the movies where the infinity stones actually show up, like Captain America, Avengers, Thor: The Dark World, Guardians of the Galaxy, Age of Ultron, and then start back up with Civil War and watch through them in published order from there, personally. The other movies set up character stuff that's largely hard to forget, so I don't think they're necessary to prep for the later ones, but having the background on the infinity stones helps keep you from pausing during some of the later films going "wait, what? When did that happen?"
Or just watch all of 'em. Doing a full binge of the MCU is a fun way to spend a weekend if you don't have anything else on your plate. If you're watching on Disney+ you can use their groupwatch thing to watch with other people you know through the internet, so you can have fun with it like that if you want.