Engine Cranks but will not Run

[D3TDY]

Hi, my car is cranking but wont start. after cranking for a few moments I receive the message on dash reading, "Oil level low please switch engine off". initially had this problem so I used Non conductive contact cleaner on all of the sensor plugs Including the one for the oil level sensor, this was done 2 months ago and that seemed to do the trick until today. So I have replaced the Oil level Senor under the oil pan and changed the oil filter along with 5L of fresh oil... still no luck. One things that has changed from 2 months ago is that now the glow plug light is flashing amber??? got a friend to use Vagcom, he cleared the faults but the ones that remain are the P009000 and P305300.
The car cranks but no life I need help guys

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Further to add today I sprayed some engine start spray into the air intake while cranking the engine. I could clearly tell the car tries to keep engine running but can not hold the revs and dies.

I tried to check if the injectors were starved of fuel, looking from the top of the engine injector 1 was struggling, injector 2 was bone dry, 3 and 4 were fine. bled the injectors and they were all fine.

Ran diagnostics and VCD's come back with P009000 Fuel Pressure Regulator "A" Control Circuit Open Status Intermittent and Camshaft Position sensor P300700 status Static.

IM thinking the Fuel Pressure Regulator, the Fuel Pressure sensor and Camshaft Position Sensor need replacing. Anyone with any ideas

will more likely need a professional to look at it whatever the conclusion I will keep updated as if anyone else suffering same issue as mine can benefit.