I'm not really good at anything. Aside from just trying things out and getting feedback from managers/coworkers, how does one identify things that they could be good at?
I've been a dev for 10 years and have a masters degree. I am just a midlevel dev. I spent most of that time working on obscure stuff the company needed, like Filenet and Neoxam. I'm now working with stuff like ECS batch, Lambdas, and some front end written in Java, Python, and Angular. I'm not seeing much progress. I think this mostly because I feel like this knowledge will just end up as throw away. The concepts and the bulk of the development are easy to grasp. Occasionally I'll get stuck with some implementation detail and just let it drag out.
I also realize that promotions are no longer a possibility for me. People are starting to wonder why I'm still a midlevel after 10 years. Recently I was told that I need to be more upbeat and improve team morale. Basically I'm being told to change my opinions, insights, and even personality. Kind of shocking when they make a big deal about DEI, including diversity of thought. This caused me to realize that all the managers are oddly happy and upbeat, so this must be a requirement. So they won't ever move me into any leadership position like manager, or even senior developer.
I think I'm tired of being a dev. The pay isn't even that good <$100k. I think some sort of an analyst position would be good. I tried checking put corporate strategy analyst positions, but it turns out they are more of a project/stakeholder manager, and they use these positions as feeders for executive positions (the rest of the team had degrees from places like Harvard and Wharton).
Any suggestions of tactics or positions to try?
Being "good at" things isn't the problem. I bet you're good at many things! But it sounds like everyone around you is also good at those things.
Looks like you've identified the two possible solutions: 1) become good at something that sets you apart, or 2) surround yourself with people who don't have your skillset (ie, new career path.) I don't know enough about you to make a good suggestion for new career paths, so I'll focus on the "new skill" angle.
To develop valuable skills, follow the pain. Every team has things they hate to deal with. Find those things. Learn how to make them less painful. If you can find pleasure in the difficulties of the painful thing, that's ideal. If not, you can at least take pleasure in the fact that your coworkers will love you for saving them from the pain.
Then you'll have an easier time getting new jobs. You can walk in and say, "I'm good at that thing your team hates dealing with." It's not enough to get you hired every time, but it sets you apart.