I decided to see how many commits GitHub (and git) could take before acting kind of wonky. At ~19 million commits (and counting) to master: it's wonky.
The GitHub API has periodic issues merging/creating PRs. (I use PRs since that is more reliable than keeping a local master up to date via pulling at this point).
GitHub reports... 
infinity commits. Doing a full clone from GitHub Actions is taking around 2 hours.
Using:
git pull origin master
to update my local master hangs for a while before even printing anything.
If anyone has seen a public GitHub repo with more commits to its main branch, let me know.
If anyone wants to see how slow wonky git acts at this scale, feel free to clone.
Edit: Update to this post is: https://sh.itjust.works/post/672069
It might be worth it. Not sure their systems have been stressed in this way before and they might want some engineers to look at it. It could lead to some more efficencies in smaller repos. Or it could lead to nothing. Might be worth contacting them to see. Even if you ultimately don't care about this repo.
Fair enough. I created a thread on the support forum. Since I don't have a paid account, I can't contact support directly.