¿Can a guy and a girl just be friends?

¡Hello! (forgive any ignorance on my part, i didn't grow up around Islam so i'm mostly self-taught from youtube, haha!)

i heard not that long ago that in Islam, it's generally taboo for men and women to be together unless they're related or dating/married. i'm not too clear on the nuances, if they meant if one is unmarried, or both, or if getting a haircut from the opposite gender is okay, but from my understanding, guys stick to one side and girls stick to the other, at least in some parts of the Muslim world.

So my question is, (assuming i'm not very wrong,) according to Islamic practice and social taboos, could a non-muslim guy be just friends with a muslim girl (or vice versa)? i mean strictly platonic, no physical contact, we just wanna play bocce ball together, would that still be frowned upon? (I'm also assuming different sects and schools might have varying answers to this)

i'm an individualist so i'm going to treat everyone i meet with the same mindset regardless until i learn their customs, so i'm moreso just curious.