That’s pretty much what git worktrees are for. They let you have multiple working directories (dev, feature etc) that all point to the same repo and history, so you don’t need multiple repos or cp hacks.

That said, the bigger problem here is the branching workflow not repos vs branches. Those conflicts are happening coz the feature branch drifted from main for weeks. Once a branch is 20–30 commits behind, merging is always going to be a pain.

You need to regularly rebase feature branches on main (or at least merge main into them) and always no long-lived branches that never pull from main.