Hey Jasher!
I am having the exact same issue as you! Just received my brand new MacBook Pro (15-inch, 2019, 2,4 GHz Intel Core i9, 32 GB 2400 MHz DDR4, Radeon Pro 560X 4 GB, Intel UHD Graphics 630 1536 MB).
I was using it the first evening while plugged into the power adapter. Battery was 100%. Then I closed the lid, disconnected the power adapter, and went to bed. Next morning the battery was at 5%. What is going on?
I'll go ahead and try your suggestion on turning off "Find my Mac". I'll test the next couple of days if that helps.
I totally agree with you: Apple needs to fix this! It can't be true that their brand new MacBook Pro drains the battery completely if "Find my Mac" is turned on.
Anyway, thank you for creating this thread and sharing your solution. I'll keep you posted.
Thanks,
Jesper