Ugh, I had a Latitude 7210 2-in-1 and upgraded the 2230 SSD to a Western Digital SN530(?) one. Turns out after hours of troubleshooting Modern Standby, poring over Sleep Studies (“why is it draining 8% of battery an hour asleep?”) that the specific drive I put in didn’t “support” “Modern” Standby?
Anyways I have a ThinkPad with S3 sleep now and the fans actually turn off when I put it to sleep so that’s a win.