When v0 syncs it will take the exact latest state of the repository. If you do not want that change, you can click “Restore” on your previous version before the sync and it will roll back, and you can unlink the branch so it doesn’t pull/push automatically
If you’re going to work on both v0 and locally at the same time on the same branch, make sure you pull the latest changes locally before committing
The most robust workflow though is to not link v0 to main, and instead do all of your work in a branch. Then when you’re happy with changes you can click the “Create pull request” button and merge it properly after reviewing changes