I stopped watching Marvel movies because I found the plots virtually nonexistent. And don't get mad at me, dear reader, if you love them. That's okay, I'm not taking that away from you. I'm just saying how I felt.
So I don't know if I would sign on to your theory. I did enjoy a lot of the characters but it didn't carry an ironman or Thor movie for me.
I would like a sequel of Hail Mary though.
spoiler
My guess is that Grace's life on Erid is just not interesting enough. In that he will probably just die there. The gravity, the nutritional problems - he is so worn out he probably wouldn't survive his trip back, coma or not. I would like a story set in the same universe where humans deal with the multiple crises while Grace and Rocky are getting the Taomeba, how they infect Venus with it once the Beatles came home, how Strat deals with her predicted abuse of power lawsuits, and how later the Eridians show up with Grace's body encased in Xenonite, bringing their saviour home, to a chaotic Earth that's just recovered and thinks it's Independence Day. The problem is just that we need to find a way to tell this story through the lens of a lone male wolf character because that's what the author does best.