I'm 36 as well, I've always worked as software engineer (full stack, but front end oriented), and last year I changed role. I was lucky enough to be contacted by one of the big tech giants, and I discovered that the evolution of a software engineer could be picked among a number of different options.

I think your premise is wrong: "I can not switch jobs because it would mean to get back to junior salary". Why do you think that?

Of course, part of the equation is also your location. I don't know where you live, but if you're willing to move, you probably can find a lot of opportunities to sell your senior experience.

It's not really clear what is the advice you're looking for. - Do you like your job? Stick to it and grow in your current role. - Do you like your job but not your company? Change company! - Do you want to switch to another job? Well, you probably won't choose something super different (e.g. a doctor!) but you with your experience you could apply for team leading roles, sofware (or infrastructure) architect, production engineer, developer advocate, partner engineer, etc.

My suggestion is to understand exactly what is your need / problem here, and to give it a name. Then start from there. You're a programmer, think analytically :) And don't think about bad choices (I don't think it was a bad choice, though) you can change what's next but not what you already did (yeah apologies for the philosophical sentence, but that's it)