With your employment history, you'll be very eager to please. You will say "Yes" and "No problem" to anything, which is not a problem, if it's actually not a problem. But this:
> when there's a conflict between expectations and requirements from management, and lack of agency to actually be as productive as I can be.
tells me it is a problem. Your quote is always true in any company. This will always happen. You will always burn out.
Here is what you do. You don't answer "No problem". You answer "Write down exactly what you want and a timeframe when you need it and I'll see if I can deliver". This will do two things:
-50% of your work will disappear. There are many middle managers who just go around delegating, thinking that is their job. In reality this is procrastination and they are useless. They will not even be able to write a spec sheet (look into how a good one looks and demand exactly that). These are the most idiotic projects in the company and now you will not be involved
-the projects that come with a spec sheet have self documenting ~code~ expectations. If you force people to write something down in a specific manner, most will realise their lunacy
Then you communicate. Don't hide anything. Tell everyone involved exactly the ups and downs (this is where lack of agency comes in and where it disappears with competent management. If it's incompetent you'll at least not feel responsible or shame) of the project. This isn't poker.
There. This might be too personal. This might be completely wrong. But please realise that it's you doing this to yourself.