2006 2.2 D4D engine stalls on idle, doesn't start without help

[Earlycreek]

Help! I have a idle/stall/starting problem that has me stumped. It involves a 2006 Corolla Verso with a 2.2 D4D engine and over 350,000km on it (I'm in France). Recently, when I slowed to stop, the engine stalled. After several attempt to start it, first without touching the accelerator pedal and then with it pushed to the floor, it started. Below about 1800 rpm however, it stalled again, so I drove home while keeping the engine above 1800 rpm. What I've tried so far: I didn't suspect the injectors because several months earlier I'd had them all replaced. (More recently, following an engine light warning, I'd replaced the alternator too - after which the car ran fine for several thousand km's.) Having already cleaned the EGR valve years ago I assumed that was the problem, so I cleaned it (and as much as I could of the manifold without removing it). No improvement. I REPLACED the EGR valve (and the SCV for good measure). Still no improvement. I had it towed to the Toyota garage where they said the injector pump needed replacing. Too expensive for me, so I towed it back home, removed the pump and inspected/cleaned it, then installed it and pulled the car for a couple miles to start it (the Battery was ebbing). It started a couple times but stalled under 1800rpm as before. I ordered/installed a used injector pump, charged the Battery overnight, and this morning, with the help of some starting fluid and with the accelerator pedal to the floor, it started as before.. but stalled under 1800rpm. I removed and cleaned the motor and chassis connections to the earth cables, just in case that's a thing. No improvement. When it's running, it runs great - no indication of fuel flow, electrical, or engine timing problems. No fault codes, no warning lights. Anyone have any idea what might be the problem before I invest more money? I attached a short video of my starting and idling attempts..