I don’t think I’ve seen it mentioned but my theory is possibly a false glideslope capture similar to the MyCargo 747 at Bishkek. That’s backed up by listening to the recordings when one of the pilots says “we can make it” which suggests the aircraft has nearly acquired the G/S ‘diamond’ (whilst forgetting to check to see if it’s a sensible glideslope indication using the 3x table). The controller clearly doesn’t feel comfortable as he reiterates they’re 3000-3500ft at 5nm but the pilots reply they’re established on the ILS.
They’d then become so task saturated trying to slow the aircraft down to Vapp that they’d develop tunnel vision and selective hearing, therefore both crew members completely fail to notice the overspeed klaxon sounding in the background plus the inevitable TOO LOW GEAR.
Then as others have said, a little float down the runway, a late decision to go around when they realise the gear isn’t down (or they’re running out of runway) and the engines then take time to spool up. This would then cause the engines to scrape the runway momentarily damaging fuel and oil lines. The engines would probably develop some or TOGA power initially allowing the aircraft to climb out but they then destroy themselves if the internal mechanisms have been damaged (or simply run out of fuel or operate at a limited power). The crew then attempt a tight circuit, lower the gear which drastically reduces the L/D ratio and the aircraft stalls into the urban area just short of the airport. It’s likely at this point the aircraft was probably in alternate law depending on what was damaged reverting to direct law when the gear goes down. This is a much higher workload situation requiring manual trim and a different feel in both pitch and roll and also doesn’t offer the same protections as normal or alternate law.
Causal factors include a lack of sense checking as to their current position in relation to the airfield and both pilots being a bit rusty due to a lack of flying because of COVID. This then lead to a high energy state. They may have been offered various shortcuts by ATC as well due to vastly reduced traffic levels which only exacerbated the situation. Then tunnel vision, selective hearing and a breakdown in CRM occur as both pilots go from a benign scenario in the initial descent to being totally overloaded in a short space of time but suffering from ‘get-thereitis’.
As I said, it’s all pure speculation but this would fit in with what I’ve read so far. What I can’t understand is why the flaps are retracted. Possibly the engines only quit as the aircraft had just cleaned up passing the acceleration altitude.