I had a conversation with management and they told me I don't open up, which is fair and true and told me to be more empathetic with my coworkers.

Except that I can't and I don't care about most of them. As said, I just want to work and go home. I consider most of them childish, gossipy and immature. Of course I didn't tell management this.

It seems possible to me you've missed the message delivered by your supervisor. You plainly state here that you despise your coworkers and your supervisor is saying you need to approach your coworkers with more empathy. To me, that sounds not like you're just trying to keep to yourself, but that you're probably acting like an asshole somehow in giving the cold shoulder to everyone.

I think you're really struggling with "black and white" thinking here, to think that you would have to debase yourself and pretend to have a bright and bubbly disposition in order to be pleasant and respectful toward your coworkers. You don't have to be mean and disdainful in order to maintain your personal boundaries at work. Your supervisor might have been on to something, because developing empathy with your coworkers can help you let go of your disdain for them and will probably help you function more effectively in your role.

I worked in healthcare a long time, and the field is certainly dominated by extroverts, but I've known plenty introverts in all hospital roles who got along just fine. Healthcare is not a job you can do by yourself. You are always going to have to function as part of a team. If you hate other people so much that you're just going to move from job to job hating everyone you work with, and you feel like you have no other option than to do this, maybe consider speaking with a therapist to try to develop new ways of relating to the world instead of just being miserable.

Have you talked with a therapist about workplace communication strategies and boundary setting?

I'm a contractor, I take my earbuds out and tell them I'm still billing...

You may be autistic. Maybe worth googling aspergers.

I consider myself an introvert, and I had to work hard to build that social muscle. Once its built though, you dont have to work as hard to maintain it, and people become less draining. Is it fair that extroverts dont have to work as hard to do this? No. But you have advantages they dont. It sounds like you need to either find a career where you dont need to work in a team (unlikely) or develop your social skills.

I had this conversation with my boss a couple months ago, and it turns out the only change I needed to make was eating and caffeinating before commuting. I was being grumpy and gruff in that period before we opened to the public when my only interaction was with my coworkers, and it was mostly because I was waiting to get to work to eat and drink my morning tea.

Working in a team, means you have to be able to work with other people. It's just a functional requirement of any such job. I get the impression that you are in denial about this reality.

Should you "come clean" with future employers? Yes. Be honest about what you can or can't do and set boundaries. That also means being honest with yourself about what the job requirements really are. You will continue to be miserable if you don't do these things.

If your management can't understand "I'm not an extravert", they are the ones who lack empathy.

I've been around medical people a fair amount over the years. Nurses vary but yeah they do tend to be outgoing or at least solicitous. Doctors on the other hand are often total nerds, almost like the stereotype of programmers. Of course, being a programmer, that's the type of doctor that I like. If you want to stay in the health field, maybe consider medical school for when you can swing it.

There is such a thing as empathy training: https://kffhealthnews.org/news/efforts-to-instill-empathy-among-doctors-is-paying-dividends/

https://www.apa.org/monitor/2021/11/feature-cultivating-empathy

https://www.wolterskluwer.com/en/expert-insights/how-to-show-empathy-to-patients-even-when-youre-stressed

https://www.nursingprocess.org/empathy-in-nursing.html

There is a specific article I remember from one of the KFF sites and those links came up while I searched for it. Unfortunately I didn't find the one I was thinking of, but maybe it will turn up later. What I liked about it was that it was aimed at nerdy doctors (it was from an internal newsletter for KFF workers, though on their public site), so it was expressed in precise terms. I learned useful things from it myself.

You can find plenty more with fairly obvious web searches.

Most of my co-workers don't like me. My boss doesn't even like me. But I'm known for the quality and consistency of my work. So I pop my earbuds in and go about my day, and they leave me to it for the most part. Every now and then my boss asks me to take on a special project that requires more group interaction than I'm comfortable with, and I just have to grit my teeth and get through it.

I've become more numb to being disliked over the years. I try to accept and respect that they are who they are and that's ok as long as they also respect my social boundaries. And even when they don't, I have learned to kindly, but firmly, assert those boundaries.

I wouldn't bring it up in an interview. Knowing how extrovert-centric the job market can be, there's no need to shoot yourself in the foot by making it an issue if it doesn't come up. Once you have the job, if they decide to fire you because you're not enough of a social butterfly, despite your good work ethic, then that's their loss.

A large set of standard comments and selected set of home activities. I note important to them events and sometimes followup if appropriate.

You seem to be doing black and white thinking. Humans are squishy, be extra nice to them.

Few of these people want to be best friends, they just want some connection. Go ahead with a minor one that you have decided on.