When running:

err = wt.Reset(&git.ResetOptions{ Mode: git.HardReset })

Untracked files are over written.

when running the git equivalent
git reset HEAD --hard

untracked files are left alone.

Also, when running:
wt.Checkout(&git.CheckoutOptions{Branch: plumbing.ReferenceName("refs/heads/main"), Force: true})
Untracked files are over written.

when running the git equivalent
git checkout main -f

untracked files are left alone.

I think that the behaviour should be the same, as untracked files are not apart of the repo and this is causing me issues with my work.