@OnTheRun provided a good resource and clarified GoTG, which I’ll just refer to as Guardians now.
There’s also TV shows linked into the Marvel shared universe, aka the MCU (Marvel Cinematic Universe).
IMO, you don’t need to watch them all but watching them all will kind of just tie everything together, especially when you add the extra credit scenes after each movie.
The link provided will give more information than I ever can but what a lot of haters will do is just lump all these movies as superhero movies. Don’t get me wrong, they are and I certainly wouldn’t consider them fine cinema, but within the MCU there are genre films; Winter Soldier and Civil War are essentially spy/political thrillers, Ragnorok a comedy, and Ant-Man is a heist film.
Of course, I wouldn’t compare Winter Soldier to an actual spy thriller but it’s about as close as you can get to one within a super hero film.
The MCU TV shows are a mixed bag, but What If? is a great show.
A lot of confusion though is one has to understand the MCU is its own thing. The older Spider-Man movies, Venom, and others are Marvel intellectual properties but their rights are owned by Sony. That’s why the Andrew Garfield and Tobey Mcguire films are disconnected from the MCU which was created later, but I’ll stop there because you’ll have to watch Spider-Man No Way Home.
All those Batman, Superman and other DC intellectual properties are a completely different entity and owned by different companies.
End of the day, it’s entertainment. I get many film goers look down on these movies but it is what it is. Going back to the Nolan Batman or the MCU Winter Soldier, those were excellent movies but they are pure escapism.