I think there has to be some sort of miscommunication going on when people talk about "feelings" and casual sex. If you didn't feel anything towards them then it wouldn't be worth it to have sex.

I don't even fuck around with lube or use toys or anything when I masturbate because the hassle just isn't worth a better orgasm. So no way in hell I'd be putting in the time and effort it takes to get girls -Which is like 1000x as hard as having to wash some lube off my dick- if I was just viewing them as a physical sensation source.

It's the feelings that make it worth it. So of course there's some feelings. What you want to be doing is avoiding catching feelings so strong that they tempt you away from whatever important lifestyle plan that didn't involve the person you're having casual sex with. This gets shortened to "catching feelings" because obviously you're going to be feeling something about people if you're choosing to sleep with them. Then other people take it at face value that they're supposed to feel the same way about their casual sex partners as they do strangers they've never talked to and wonder what they're doing wrong.

Think of it like making a friend while on vacation, or adopting an elderly dog/cat. Yeah you're signing up for some sadness reasonably soon, but its worth it for the connection in the mean time. It's ok to be sad sometimes. You don't need to hunt out every potential source of sadness and get rid of it. Dulled senses, apathy, lack of caring. That's what you want to avoid. Or sadness so strong that it cripples you. A little bit of sadness is just part of life.

With these though:

they don’t show a lot of emotions or want to talk to me if we’re not hanging out in person

The problem is your lack of emotional management and therefore your lack of understanding of other peoples emotional management. If you show a lot of emotion and talk all the time, you're risking feelings strong enough to get in to a relationship. So you don't do it. You maintain some distance. Take the best parts, getting to enjoy each other in person, but then intentionally try not to think about or interact with the other person while you're not together. Like rationing or a quota. You stick to hanging out with them once a week or so, never talk inbetween, do the same with one or two other people, and you keep the emotional attachment manageable.