> My first troubling discovery was in 2025, when I made several errors then did a push -f to GitHub and blew away the git history for a half decade old repo

git reflog is your "backup". it contains every commit and the resulting log (DAG) going back 90 days. If you do blow away a remote commit, don't fret, it's in your reflog

  # list all of the remote HEAD commits you've ever worked with 
  git reflog origin/master

  # double check it's the right one
  git log -5 origin/master@{2}

  # reset the remote to the right one
  git push -f origin $(git rev-parse origin/master@{2}):master

  # (optional) reset your local branch
  git reset origin/master@{2}

  # at this point your local branch has time-traveled, but your working dir will be in the present state (e.g. all the relevant files will show as changed)