This is intended to be a follow-up to Endgame but disregards Thor: Love & Thunder and Guardians of the Galaxy Vol. 3.
Thor and the Guardians cross the galaxy and go to countless planets to commit heroic deeds. One such way is to help war-torn planets' refugees. The team is divided in the different ways they could provide aid — Thor, Korg, Mantis, and Groot prefer to keep on sheltering and transport the refugees to galactic safe zones. Quill, Rocket, Drax, and Nebula prefer to fight in the conflict. Kraglin and Miek are neutral.
The main plot would regard a kingdom in some faraway planet and the heroes are hired as mercenaries. And the job didn't turn out as they expected it to be. I haven't thought of this one through.
The main genre of the movie would be swords-and-sandals fantasy, like The Sword and the Sorcerer, Krull, and especially Conan the Barbarian. The Guardians come in sprinkling some dash of comedy western, like 'Call Me Trinity', and dogfight films like Top Gun and Iron Eagle (because they have a spaceship).
Further influences come from 1980s space opera animes and cartoons, as well as 1981's Heavy Metal. I'm also drawn to the futuristic post-apocalypse aesthetic of Tank Girl. The title itself is a reference to Jason & the Argonauts.
There'd be a more relax sense to it because it doesn't try to overly connect to the larger picture of the MCU. It wouldn't pave for future movies and more of a detour. The only familiar characters are the heroes, everyone else are unique to this, to emphasize it's not a "Thor 4" or "Guardians of the Galaxy 3"; it's its own thing.
It's a missed opportunity in the MCU is not exploring more of Thor and the Guardians together. If 'Thor: Ragnarok' is MCU's "Flash Gordon" and Guardians of the Galaxy is MCU's Star Wars, the opportunity here would've been what if Flash Gordon was in Star Wars? I think I wrote this pitch to answer this question specifically.