Since posting this a while ago:
..I've been exploring the power of HLG picture profile introduced two months after X-T3's release. I'm pleasantly surprised by the refreshingly new colorimetry and better (not higher) dynamic range distribution. To me, X-T3 now feels like a completely new camera shooting with HLG. So long F-log!
Here's a better comparison than the one from my previous post:
F-log with Alexa LUT generated by LUTCalc, no grading, WB 5300K, Shift 0: