That's just an acquaintance, honestly.

I hope that's not true. Though I'll admit most of my deep male-male friendships date back to high school and new ones are very rare. Most new deeper friendships I've formed have been with women, who I think frankly make better friends.

Men can develop deep friendships with each other as adults, it "just" takes enough mutual interest and flexibility to spend a lot of time together. That is much harder if your time is already spoken for my family, a partner, children, work, hobbies, etc. Think of all those sitcom friends who just show up at each others' houses and hang out.

Friendship is fundamentally when two people want to spend time talking with each other (without an ulterior motive like sex or commerce).

Sitcoms are not real life and never were. They are made up situations designed to make writing funny scenes easy. Sitcoms are not how people actually ever socialized or behaved.

My wife's closest 10 or so friends are all from school era, 20+ years ago.

My close friends are all people I've met as an adult - I'd consider them deep friendships: we've travelled together, catch up regularly, know each others' parents and kids, discuss the issues of the world, etc.

But, like school, you need enough time around a common place or interest to develop all that. In my cases, it was usually shared, social offices or having friends in common.