I usually rebase the branch onto the upstream branch (master or main or whatever) if there are merge conflicts. You can then resolve the conflicts commit by commit. This requires force pushes, but they are are not normally a problem because only one dev tends to work on a particular branch before it's merged.

If you do have multiple devs working on the same branch, use `git pull --rebase` to stay in sync with each other, don't use merges and leave lots of merge commits. If you need to resolve conflicts with upstream, make sure other people have stopped working on the branch, rebase it, then merge.