This I agree on. I'd also add based on my experience, consultancies add to the issue. After 20+ years of meddling and pushing the latest idea we are still not productive
1. Take time off, but don't sit on your arse watching Netflix. Plan to do something. During future interviews if asked about the gap you can say, 'I did this and that' and it marks you out as a more rounded person.
2. I follow the CIA principle of Change what you can change, Influence what you can influence and Accept that you can not change or influence. So try and change your working environment (approach management with positives) otherwise suck it up or move on.
3. 'Rockstar programmer' what a load of crap. All that means is someone has depth of experience in a few areas. No one knows it all, and at the end of the day you are being paid to build and maintain a product.
In your case many products and that in itself is something to be proud of.
I work with some really smart developers and I don't think any have created public libraries and solutions from scratch - what makes them smart is asking the right questions and not just excepting the first answer given and then piecing together a solution
4. 'Stuck in a rut' a rut is a grave with the ends knocked out
5. 'Evaluating your worth', the only way to do this is to look outside the small pond you are currently swimming in. The regular long hours sat looking at screen are not good for your mental, physical or social health, "regular breaks" are not the solution
Sorry if I sound like a grumpy old man, but I am.
I am 50 this year and when I hear similar stories to yours I just want to do the 'dad thing' and say, "things will be okay, you know more than you think BUT its down to you to make the change and good things are not easy but are worth the effort".