At 200k the engine may be a bit tired, needs glow plugs to start. They aren't working. The temp sensor previously mentioned may operate them when needed and not be working. Water ingress to the electrics has stopped them working.
When you turn on the ignition do you see the glow plug symbol come on & then go off after a few seconds?
When you say 3 tries. Are you almost immedietly releasing the key if it fails to fire straight away? Keep it churning for 5+ seconds and see if it goes. Don't give it any throttle.
The way you are doing it, it starts eventually as you have built up some heat in the cylinders.
The fire in the starter sounds like a lot of carbon dust had built up over the years & you got it hot by using it more than normal. Worn brushes could have been arcing and ignited the dust.
