To be fair, I think it is chronically underprovisioned clusters that get overwhelmed by log forwarding. I wasn't on the team that managed the ELK stack a decade ago, but I remember our SOC having two people whose full time job was curating the infrastructure to keep it afloat.

Now I work for a company whose log storage product has ES inside, and it seems to shit the bed more often than it should - again, could be bugs, could be running "clusters" of 1 or 2 instead of 3.