Exactly this, limit your apache processes to match the ram you have available so the machine returns 4xx or 5xx to excess requests but otherwise remains respons

Exactly this, limit your apache processes to match the ram you have available so the machine returns 4xx or 5xx to excess requests but otherwise remains responsive and normal. Problem solved. The options are right there in the conf. Start with a super low limit then slowly increase while watching reqs/sec. When reqs/sec stops increasing or you run out of ram then there’s your sweet spot.