Ragnarok is a movie that I was able to enjoy on not just one but even on two viewings, and thus it qualifies as an exceptionally good CBM.
It's not just that the jokes are funny, though they are. The visuals and the music are improved from what we usually get from Marvel ... I can watch the end credits as a music video, and in fact I have on a couple occasions. It also expands the Marvel universe -- setting is very important to me. I like to feel like I'm visiting
places in science fiction movies (like in the original six Star Wars movies, and Rogue One, and Solo), and Ragnarok gave me that sense. Asgard felt like a place with a history, and Hela's backstory implies a broader universe. The garbage planet felt like a place, it had its own culture, hierarchy, etc and we meet all sorts of creatures there. The network of worm holes suggests how large and diverse the Galaxy must be in terms of number of worlds (visual storytelling). They say that it would take 18 months to get to Asgard via Xandar otherwise, that's nice, really outstanding line of dialogue.
The garbage planet also reminded me of the garbage planet from the 1980s Transformer movie, it was just as good
and they had the same story arc, and a good musical score too
Thy get into combat there, they liberate the slaves and overthrow the tyrant, and they leave with a ship with the liberated slaves as help to go fight the true enemy