I previously commented a solution to another problem, but it assists here too:

https://news.ycombinator.com/item?id=44746992

This command will make your MacBook hibernate when lid is closed or the laptop sleeps, so RAM is written to disk and the system powers down. The downside is that it does increase the amount of time it takes to resume.

A nice side benefit though, is that fingerprint is not accepted on first unlock, I believe secrets are still encrypted at this stage similar to cold boot. A fingerprint still unlocks from screensaver normally, as long as the system does not sleep (and therefore hibernate)