Scratch that. I just rebooted my Mac Mini and 18.5 appears to be running fine now. Am getting a full 60 FPS/UPS now. It was definitely laggy before, but a reboot fixed it. Weird.

Thanks for the updates! Especially the one where you can hit enter to make the logistics requests save!

Can confirm, 18.15 has a definite performance related bug. My current base is barely past the point where I first launched a rocket. Nowhere near the megabases I have built in the past. The lag is unbearable. Am downgrading to 18.13 now.