GitHub API limits prevent Gitea project from migrating issues

I hope my title does not fall in the "editorialized titles" rule, but I had to summarize two toots in that Mastodon thread into the 80 chars limit. The full text is:

"I'm not sure if you've tried to migrate a repo with 20K+ issues/PRs (and all the comments/other metadata that comes with it) from github, but their ratelimits are extremely low. So we are making progress towards migrating away, but we don't want to lose any information in the move. We are in fact using gitea every day, and have moved all but the main repo to gitea.com."

and

"our migration has been in the process for a while, but every time we run it we find that our attempts were missing some data, so we need to re-run to fetch missing data, if we had higher limits it wouldn't take so long to find these issues. Github doesn't provide tokens with higher limits, so we have to work around that. We even had people with GHE subscriptions ask, and they got the same response."