This sounds like the main problem. They’re assigning you tasks that no one else wants to do or that aren’t high priority. That means the task is difficult or unpleasant in some way, or they don’t actually care that much about it and won’t prioritize anyone else to help resolve your blockers.

It may be difficult, but I think you should have a conversation with whoever you report to about what their expectations are and how they expect blockers to be resolved if no one prioritizes your tasks. You may need to approach this less defensively and make it clear that clearing these blockers is not your responsibility. If the person you report to isn’t a team lead/manager then I would escalate the problem to a manager and make it clear you’re not getting the resources you need to do your work.