Going from 1.0.0.3ABBA to 1.0.0.4B, I also lost some boost initially. So went back to ABBA. After some time decided to give it another try.
That time did not have any idea how to use PBO and how actually works, and I just have it on advanced mode with +200MHz.
What made boosting work like before was turning PBO from advanced to auto.
After next bios update (same AGESA), new chipset drivers, win v1909, and latest 1usmus power plan, the boost has return to previous behavior with PBO in advanced mode +200MHz.
Now of course I have completely mess with PBO settings. The point is that you need pretty much everything to the latest possible.
You should check every section of UEFI and find any set you could missing.
This is annoying with UEFI updates but this is common sense practice as a set could change name or place in UEFI and try to apply a profile that it’s not the same could lead to unpleasant situations.