Second, I'm not sure what your current stack is, but it sounds like it's old enough that you may need to retrain yourself some, depending on your area of focus. Whether it's through a legitimate course, or self taught, the evolution of a 10 year old product has likely left you in the cold.
Of course, it depends on exactly what you'd like to do, which is the most important thing (and something a therapist can help with). If it were me, I would note down everything about my current situation I really don't want to or can't give up (remote work, low stress, good salary, etc) and what I'd like to or need to find in the next job (a welcoming team, new and shiny tech, learning every day) and then prune the list to your satisfaction between negotiable and non-negotiable for a new situation. But you have to be realistic, if you want something like $200k/yr in Iowa working for a low stress agency, you're never going to get it.
After that, just start looking, maybe even put yourself out to a recruiting agency if you don't know how to begin the search. It's not really hard to find new positions with a lot of experience, it gets harder to find the ones you want.
You've got a lot of experience under your belt, hopefully you made the best of it, because it could make employers quite interested in you.