If your LB is down, you're just kind of screwed. You can't enqueue things if requests aren't getting through at all. Same deal with authn/authz issues, which they also had. If you can't answer the question "is this message allowed to be added to the queue" you can't enqueue stuff.
GitHub does use queueing for all kinds of stuff internally, though, because they're not morons.
YOu are making an assumption on which LB is down, and so am I.
Where is LB placed? Is that hte LB in front of API GW? or behind GW? GW can have rate limiter or cloudflare FW can handle the rate limiting.
The doc does not show which part of LB is down so it's all guessing at this point so i won't go forward with this.
GitHub does use queueing for all kinds of stuff internally, though, because they're not morons.