How do you deal with insecure/jealous co-workers?

Have you talked to your manager about this? Just be direct about the impact the other engineer's behaviors has on you, but at the same time try to emphathize with their attempts to grow their careers (this is so that you don't appear fully bus throw-y). If your manager has repeatedly brought this up to the other engineer and there's no behavior change, I'll look to start documenting their behaviors you observed and if there's anyone else on the team that will support your claims.

Sorry to hear that you're dealing with this - This is a situation that happens all the time. Here's my advice:

• Create a paper trail - Screenshot DMs and bad behavior on common docs (like tech design ones). You can record meetings as well. In general, you always want to be creating a paper trail anyways to remember your accomplishments for performance review - This is simply an extension of that behavior.
• Talk to your manager (if you trust them) - It's the manager's job to solve issues like these. 1 way to view managers is as a "people API" where you can call that API when members of the team aren't playing nice with each other. However, the "if you trust them" bit is very important, because if you don't (and they're a bad manager), you might get labeled as a "problem employee" who's just complaining. Also, if you're going to have this conversation, the paper trail will help a lot. Make sure to follow general communication tactics as covered in my Effective Communication Guide (check out Parts 4 and 5 in particular): Alex's Guide To Effective Communication