Nice content. My hardtail (with 2.3 Ikons, flat handlebar, a 100mm fork and a seat dropper) is my gravel bike now. What I have noticed when riding doing "gravel" rides with my friends (on Lauf Siglas with 20mm of travel and 42 mm tires) is as follows:
- Single track or any semi-technical descents: I run away and hide
- non-technical gravel or flowy (flat) singletrack: relatively similar performance
- road: they run away and hide
Given all of this, I am with you...use a HT MTB. I haven't gone so far as to put a drop bar on, but for what you are doing and how you are competing, seems like the right call.