I understand to some extent what you are saying but, and citing my own gear, Manfrotto or Benbo, a tripod normally has just an un-alterable flat head with a 3/8 UNC screw thread sticking out of it.
The norm is to then attach some form of head to that screw and the screw clamps the head to the tripod. The head being designed to allow you alter the orientation of the camera, that will be attached to head in various way, up to (expressed in drone language) pan/yaw, pitch and roll.
With some heads the camera is actually clamped/screwed to a plate (QRP, Quick Release Plate) and the plate is then inserted into a recess in the head and clamped in place. Normally the clamping mechanism is either a single screw mechanism or a lever operated cam, all designed to facilitate the quick removal and fitting of the plate and camera from the head. E.g. a Manfrotto 141RC head and its 200PL QRP .
Looking at a still at 1:52 from
I think the 200PL would attach to either of those MavMount plates without difficulty.
You could even mount another ball head in the tripod and screw or clamp the MavMount plate to that 2nd ballhead.
Another idea might be the Benbo Trekker (a weird but sometimes useful) tripod which has a tiltable/pitchable arm +- 90deg with a 1/4screw at each end.
I can probably cobble together lash-ups tomorrow if you want photos.
A third option might be some form of Arca Swiss mounting with the MavMount plate being mounted on/screwed to one of the readily available Chinese copy extender plates.