You see, that was my idea behind the "theoretical max height" on an (also theory) new and freshly fully PD-charged battery:
Ascending with max speed till auto low battery landing, descending also with that speed.
Up and down about the same time, 50% batt up, 50% batt down.
I'd say, if the bird really hits a max height at 1200m over HP, this 3688m is just a auto calculated thing. Has anyone ever checked this setting "live" with a 50% battery, only?
Perhaps it is part of the battery managment?
I get your point, it's clearly a possibility, but it would be very optimistic : ascending maximum speed was around 5 m/s, slightly less downwards - notice these values in Flight Plan's automatic flight mode are well over those you can select in FF's settings for manual flight. I can set a waypoint's elevation to 4000 meters high right now in my app, which means at least 13,3 minutes at 5 m/s, that's already more than half the 25 minutes maximum flight time of the Anafi...
Battery wise, from this practical experience, the Anafi flew from the ground to 1200 meters and back to the ground with 50% battery left, so in theory it should be able to climb to 2000 meters and come back down "easily" - considering its battery capacity only, but weather conditions were ideal, less than 20 km/h wind, no icing at 2000 meters (or as you said, climb to 4000, but then batteries would be empty).
In any case, the onboard system decided to stop the climb and RTH (together with a weird "No Take Off" message on top of the "RTH in 3... 2..."), that's why I said that they should not set the slider to this height, it should be the same maximum elevation that the Anafi's onboard system/firmware is calculating !
Oh, aside that I dont think that heat is really a problem, in 1200m. Or 1200m over any altitude, the HP is in
True that I didn't notice any particular heat whent I had it in hand for a few minutes just after landing, a, but you need to keep in mind that it had more than 5 minutes to cool down while descending, and that temperature was less than 10°C up there, so who knows...