Sequencing changes under epic

[B2F]

As I started to use bmad, I have been wondering about how it differs from openspec, so far I feel like the main difference is for sequencing big set of changes.

Suppose you need to work on a big "Epic" with many changes and some of those changes require a specific order of implementation, how do you tackle this with openspec (apart from applying each changes orderly by hand) ?

Does anybody use openspec within an agentic workflow where separated changes are taken care of by multiple subagents in an orderly way ?

Actually within one change, tasks are worked on in order if I recall, so one openspec change may cover an unlimited perimeter ? But that way parallelism becomes harder.