We don't use New Relic or Datadog (and never have, afaik), so I'm not sure what post you could be referring to for those two? We have talked publicly about our Grafana use, though, and going from an in-house stack to their cloud product. Actual OP can probably hop in later with a better answer, but it was hitting rate limits on the logging agent, not the logging system.
Ah! Thank you, that makes a lot more sense. I misunderstood https://data.mux.com/blog/off-with-our-head-how-we-re-making... as suggesting that Mux was making Mux core infrastructure ‘play nice with’ the various providers.