There is SO much to watch for Marvel, but we really loved the timeline here because it put things in order to tell a good story. Release order tends to scramble a few of those things.
This timeline did also include ALL of the series (both on TV and Netflix) that are available and if you include those it really slows down the timeline. We had watched a season or two of Shield before we watched things in this timeline so when we set out to watch, we decided to include them and while we loved Agent Carter; the first few seasons of Shield; and the 2 seasons of Daredevil that we watched- we found that: A) it was really slowing us down & the hubby wanted to watch Endgame as soon as it came out and B) aside from some very minor references to the Marvel Universe in general, the stories weren’t so intertwined that skipping them would miss any pivotal plot points int he movies, so we stopped including the series after Daredevil Season 2. [I do think that since we had already started Season 3 of Shield we did push through finishing it where the timeline had it, but not very enthusiastically].
So, in sum, you can totally skip all the series & focus on the movies on the above timeline, or you can really dig into the deep end of Marvel & go full-speed ahead to all the movies & series.
However, if you go the deep-end route I’ll have to warn you to check the timeline every now & again for updates (mostly if any big Marvel movies are released). I know during our time of watching they moved Agent Carter season 2 from near the end right up to just after season 1 and there were a few other movies that I don’t recall now that they updated they updated placement of as it made more sense.
Anywho, whatever order you watch them in (whether it’s the timeline I included or not), enjoy! And the only one that I’ll 100% stick to watching first is Captain America: The First Avenger. There’s really nothing like his story to kick it all off. Iron Man 1 is also superb but since he’s not the First Avenger, he gets to go second.