Over the course of my 20-year career as a software developer, I've always been involved in the estimation process of any work I have to complete. Deadlines are typically agreed upon before we commit to schedules.
I think it would be unusual to have somebody else say you'll personally deliver a large software feature by a certain date without involving you at all.
I can understand a Team Lead making a commitment on behalf of their team but in this particular case a "team" doesn't work on the feature, but rather each developer handles their feature on their own from start to finish.
What is happening to me is commitments and estimations are scheduled for me with dates I can't possibly make. Generally, I'm so far behind on my current task, my next task will inevitably be late as well.
I'm starting to feel constantly behind and stressed by deadlines I have no part in making or committing too.
I've brought this up to my managers but the response I get is that I'm too busy to help with the estimation process and/or these are high-level estimates and not deadlines.
Management routinely treats these estimates as commitments and deadlines and will even mark a project as in "yellow or delayed" status if a project isn't releasing on time from the high-level estimate.
I'm not sure what to do next or how to handle this.