Have you watched drifters.??
Or claymore.??
Gintama and D. Gray Man. At first, you may find them boring but it gets better though!
I have watched the two of them when I was in elementary
Ahh you said "underrated" welp, most of the classic action i know got romance init, how about black jack.?!! Thou you might not like the art..
Or trigun
It's been awhile since I watched anime, so recommend me some underrated anime.
As long as it is action or shounen, has minimal romance or no romance at all, no cringey characters, and not harem.