Ask HN: How do you plan, estimate, and delegate engineering work?

I recently moved from a regular engineering role into a team lead position. Previously, team leads handled task breakdowns, PMs brought in product designs, and senior engineers did most of the planning. Now, with the previous team lead gone, I'm responsible for interfacing with PMs, gathering requirements, breaking features down into engineering tasks, allocating work to junior engineers, and setting timelines. This is new territory for me, and I’m looking to learn from others who have been in similar positions. What techniques or frameworks have worked well for you in:

1. Collaborating with PMs to define and clarify requirements

2. Breaking down product features into manageable engineering tasks

3. Estimating effort and setting realistic timelines

4. Allocating work to junior engineers while supporting their growth

5. Ensuring alignment and avoiding surprises during implementation

Any advice, best practices, or pitfalls to avoid would be greatly appreciated :)