Special shout out to the person who committed a gigabyte memory dump a few years ago. Even with a shallow clone, it's pretty darn slow now.
If you want to be the team's hero, I've had good luck removing old commits using git filter repo.
https://hibbard.eu/erase-sensitive-files-git-history-filter-repo/
We can't rewrite history to remove it since other things rely on the commit IDs not changing.
Oh right. Oof.
I would be working to arrange an accident for those other things. Those other things probably need to be retired.