I've often seen talk about '(physically) strong women with juxtaposingg physiques', but let's talk a bit about how this trope applies to men just as often. Usually it's an anime and manga trope, but it does happen elsewhere.

1. Cloud Strife from Final Fantasy VII: Probably the poster child of this trope, and actually wasn't as bad as in the original character art in the PSX game, but subsequent adaptations have stressed the bishounen look more and more. This trope, likewise, applies to a lot of Final Fantasy characters, especially in Final Fantasy XIV where you're just as likely to see a tiny lalafell swing an axe the size of their whole body as much as stay back and cast a spell.
2. Kenshin Himura and Sanosuke Sagara from Rurouni Kenshin: Kenshin is literally described as mistakable for a woman at a distance due to his slight build and features, but he still has the strength to move as speeds faster than the human eye can perceive and jump over small buildings, though in his case, many characters 'in his fighting tier' note he's physically inferior (his mentor, Saito, etc.). Sanosuke is a much more wild offender, though, shown with a moderately athletic build but pulls off super human feats of strength.
3. Blitzo (and Styker, not pictured) in Helluva Boss: While Milllie is a prime example of strength/physique contrast, Blitzo and Stryker aren't much better being peer or superior to Milllie in physical brawn but having Vivziepop's default 'Tumblr Sexyman' build.
4. Most of For Honor's cast to some extent or another, but especially Orochi: While plenty of For Honor heroes seem like they'd have the physique to pull off their moves, there are a few exceptions, mostly in executions (and not the universal ones) where it gets absurd. Orochi's Tsubame Gaeshi execution includes tripping an opponent and a one-handed rising slash that briefly reverses the victim's momentum mid-aid and sends them flying a short distance. Might not be too bad if you couldn't do this to opponents like Lawbringer, Shugoki, Sohei, and the recently added Juren, who are all huge guys who are heavily armored and would easily clock in at 200+ pounds (if not in actual weight than including their equipment)

[Mixed Trope] MALE characters whose strength does not match their physique