Bisexual (instead of broader labels) is probably most useful as a sexuality attracted to multiple but not all genders and cares about or appreciate the differences between those genders. Polysexual also works but is sort of so vague as to be not useful.
Edit: meant to include that bisexuals regularly have a different definition than what I just gave. Bisexual in particular can really change depending on who you’re talking.
Edit 2: and by “most useful” I mean a definition that overlaps with neither pansexual or omnisexual, and accurately describes what a lot of people think of as bisexual. Like with any queer label though, no definition accurately describes all people who use it while excluding everyone who doesn’t.