Anyone feel like you're getting the hardest tasks, despite being relatively junior?

I'm in a team with 5 other engineers. I'm coming up on 4 YoE (2Y tenure), 1 of the other engineers is a bit less than me, and the other 4 have decades of experience.

I can't shake this feeling that I'm getting the hardest tasks. We have a sprint board so I can see what everyone else is working on and has worked on. It seems to me that my tasks usually consist of at least one of the following, where many of the others don't: - Ambiguous acceptance criteria - Ever-changing requirements - Difficult bugs with deep or obscure root causes - Complex architectures - Learning curves and/or tedium with chasms between milestones that would drive many to quit - Dependence on other people (especially rare SMEs) to access obscure knowledge - Research that's far deeper than a few Google searches - and more

Part of it is the nature of the application I'm owning (interdependence with other teams). Part of it may be my arrogance talking. But part of me believes that my manager is making deliberate choices about delegating beyond just "Dev A has free story point capacity this sprint" or "Dev B has worked in this area before, so I'll give him more tasks in that area".

To the devs, do you feel there's a discrepancy in the difficulty of your tasks compared to your YoE?

And to the leaders, do you consider the difficulty of a task when delegating? Do you just consider the scope? Do you give newer developers harder tasks to get them up to speed? Any other criteria?