At the risk of stating the obvious...
There are obviously two persons on the flight deck, so it is not exactly a single point failure. Contact was lost immediately after some radio communicating showing that both were on the flight deck.
Not talking about some trained people aft of the cockpit with portable oxygen, tools, communication equipment, access to the electronic compartment and probably some clever ideas. So it is hard to do this as a "single point".
let’s use Occam’s Razor on this—This simplest solution is probably correct.
And the suicide theory is just too complex for this. Too many things to be considered. Too many details to think of and plan for.
The radar that provided the altitude information was apparently an Air Defence primary radar which does have height sensing capabilities which are normally accurate to within a few thousand feet
The radar station in question was obviously just a "simple" one. No doubt, the military also has some equipment which allows to locate aircraft quite accurately, but not in permanent use. And not in the middle of the jungle... This was a station to cover a large area with low precision. Just look at the track plots.
And if better data should exist, we will probably never see it, neither did the official investigators.