Fantastic curation of the Tech lead's responsibilities. There's one thing I didn't see you mention, that I think is key, and even caters to the issue of individual contributions, and that's "pairing".
Like you mentioned, you unblock the team by ensuring that the stories/tasks are as clear as possible to remove all possibilities of ambiguity/scope creep. The other part of unblocking I believe is having pairing sessions with the team. This gives you insight into:
Thanks for writing!
Thank you! I agree that these points are valid.
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