Earlier quoted context omitted.
load balancer failure? rate limit woudl address concurrency limits? throttle or queue up messages. auto-scale failed cause was misconfiguration policy, which i admit cannot be handled by my suggestions. The cascade? it's downstream service degradation, which I mentione should have had been prevented with queues. One of the jobs that queues/kafka solve is to prevent these downstream outages.
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.
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.