I do quite like the ambiguity TBH, an ill defined niche is bound to lead to lots of confusion and that is always fun, just like when someone tells me they’re into mountain biking, covers a multitude of activities now.
My roadie mate looked at it and called it a CX bike, a work colleague referred to it as a “Road bike for tow paths”, I’ve called it a “Gravel bike” but it’s been on other surfaces and hasn’t spontaneously combusted and I’m keen to use it for a a dabble with CX racing, and maybe some touring/bikepacking…
If “Gnarmac” floats your boat then go with it, not my own preferred term (not sure what is TBH) but I see the humour…
Maybe just call it a “Bike” and leave it there…