There is certainly a segment of superheroes who don’t have inherent superpowers – usually it’s a matter of having access to high-level specialized technology, and/or being exceedingly highly trained in martial arts, investigative techniques, etc.
Tony Stark/Iron Man (at least in the original iterations*) is not dissimilar to Batman, in that he’s an insanely rich dude with access to high tech (and has mental issues). The major differences are that Stark isn’t a martial artist, and his armor is a lot better, but regardless, he is certainly a superhero.
In both Marvel and DC, there are definitely different “power levels” of superhero – in Marvel, for example, there are heroes like Daredevil, Black Widow, Captain America, etc. who are absolutely more capable than street-level thugs (or the police or “mundane” soldiers) – they’re sometimes referred to as “street-level superheroes.” Batman (and Spider-Man) are probably at the higher end of street-level superheroes.
On the other extreme, there are heroes like Captain Marvel, Hulk, Thor, Superman, Wonder Woman etc., who have extremely high levels of ability, and in some cases, can be nearly limitless.
Even so, they’re all superheroes.
*- In the comics, in recent decades, Stark implanted himself with nanites, died and was resurrected, etc., and some of his powers may be “inherent” now.