Yeah, I know. The question you are answering is something like "how could I approximate your appreciation of the MCU, Padawan?" The question that was asked is really "I can't realistically watch this film before I see Endgame, would I be missing much?"
We may have our own answers to the latter question, but as somebody who has spent an entire lifetime (six decades and counting) catching up with film series through sequels, the plain fact is that the exposition will be enough in any competently produced film.
As somebody who watched Doctor No and From Russia with Love in the cinema as a child, I question whether anybody would seriously suggest that one must actually view Ursula Andress rising from the sea in order to appreciate Casino Royale.
The 007 comparison isn't really the same though, as Bond movies are usually pretty self contained. It's not different chapters of a bigger soapy story. There is nothing in Doctor No that is of any importance for or ties into Casino Royale. The MCU has more of a soapy structure, where the ensemble episodes push a general story further, and the individual ones take into account what happened before (but still usually tell self-contained stories that aren't essential to getting the whole overarching story.) I mean, I've seen all MCU's to date except for Incredible Hulk, and most I've only seen once. I've forgotten most of them almost completely, and I still have no problem whatsoever to follow the new ones.
But I totally agree with you on exposition. If it is important to understand a story a good film maker will make sure it is explained. If it's not important and just a little nod, it's fun for the fans. And because these MCU-movies (even the ensemble films) are written as stand alone stories with a clear new conflict and a beginning-middle-end-structure, you can kind of hop in anywhere in the series you want. Especially the stand-alone films are usually little more than back story. You don't need to know how or why Thor is on a space ship in the beginning of Infinity War for instance, or how Black Panther became the king of Wakanda. The movie tells you they are, and the reasons aren't actually all that important for the central conflict of IW.
The "Nah you dont actually need to watch the movies to understand stuff" posts explains why we have threads like the Civil War one where people are complaining about there being no stakes or ramifications for stuff that happens. Half the people probably arent even watching the films. Just catching one here and there; then wondering why they don't understand the impact stuff like the Accords has had on the characters/team.
With no stakes people mean that because of the serialised nature of the story, there often is no real sense of danger and events are brushed of sooner or later. The ramifications are often just the new conflict to resolve in the next one, in a perpetual circle. Of course there are personal ramifications, and I think Civil War is one of the better ones in this regard (even though afterwards they did so little with it. Even in IW they just keep Cap and Iron Man apart, in stead of forcing them together).
I don't totally agree with the sentiment the MCU has no stakes, but it does feel more like a soap structure to me where you know there is no end in sight (Endgame will probably be the first to change that). One if its main problems is that it sometimes quickly reverts the conclusion of previous films. Homecoming Ends with Peter realising he is better suited to be friendly neighbourhood spider-man in stead of an Avenger, only for IW in the first 15 minutes to completely revert this for instance. Because of stuff like this, it can feel like big conclusions and arcs don't really matter, because everything goes back to the status quo anyway.