I know Telenko is highly regarded but I think he's going out on a hell of a limb with that analysis..
I've seen that video - yes there's no obvious damage but it doesn't mean the aircraft is intact and flat spin certainly does not equal poor maintenance.
For all we know there might have been a shrapnel damage (SAM/artillery)on a small scale that led to a hydraulic leak that led to control loss that lead to the flat spin, or resulted in some other flight control problems..TBH it's possible to get some types of aircraft into a flat spin simply through gross misshandling, though less likely with modern types
It also not unknown for aircraft to be able to absorb a small hit, perhaps holing hydraulic lines, not lose big pieces of structure, and then fly on for quite some time post the strike before finally succumbing to battle damage...
In short you can't really draw many conclusions from that video, other than the aircraft crashed.