I don't know if it's jusst me, but a company with 8000 devs having 1000 PRs per day doesn't look impressive at all? That means...a dev is producing a PR less often than a once a week on average? That's not only underwhelming but downright bad. Their uptime is much more impressive here, but it still doesn't strike me as anything exceptional.
If you use tooling like renovate/dependabot and run them daily over a large list of repos, you already get your 1000 PRs automatically, without humans even looking at the codebase.