SMT off is the way to go
I am glad you wrote this article and i do understand your frustration. We are all in the same case. 
I  sent a message to Cryrek to talk about this issue.i hope i won't be the only one.
I have a ryzen 1700 oc 4ghz. - vega FE
With SMT on, it is a disaster.
(High settings at 1440p without RT. Only shadows and post processing at medium)
With SMT off,  8 cores are used and my gaming experience is very good. 
However there is 1 core always above 90%
So in somes scenarios, i am "cpu bottleneck". 
But most of the time, framerate is above 60/70fps without stutter.
Actually, Hunt showdown  is the only game made by Crytek that is well "cpu optimised".
Crytek has spent a lot of time over the last 2 years to optimize Hunt Showdown. And honestly, the result is very good. 
Forgive my  bad english. i did my best.