2006 tdi bug No start

I have a 2006 tdi bug that will not start at first we thought it was the fuel filter so we change that out then we thought it might be the battery because it wasn’t staying charged so I change that out then I changed out the 109 relay that didn’t help what the car is doing it will crank and almost start or start for one second then shut off someone said I may have jumped a notch on the timing belt so I took the cover off took a look at that and there doesn’t seem to be any damage to the timing belt I was told I might try relay 409 but I also thought there may be a fuel inertia switch that had been tripped but I’m not finding a fuel and nurses switch someone said the diesels do not have them any other ideas I think you in advance

First off welcome!
Second thing is have you access to VCDS to scan the car to see if you have any codes tripped.

Does the intank fuel pump run when you turn the key to the on position? Does the check engine light come on with the key in the on position? I can't say I've seen it on one of these, but I would check to make sure the flap in the intake isn't stuck shut.

The flap on the intake of the turbo charger works fine seems like it’s spring loaded and it’s open at this time I will have to check the fuel pump in the morning I was wondering is there a fuel shut off if you’ve had an accident? The timing belt looks good is very tight and there doesn’t seem to be any damage to the belt and no belt dust on or around the belt I am also going to try relay 409 to see if that does anything I think I can get a used one in town for about 10 bucks. I put an ODB scanner on it and the only thing I got was some type of low pressure on the turbo. It turns over fine and then it seems to slow down turning like it’s building up pressure in the cylinders and almost kicks over.I thought it might be a backflow problem in the catalytic converter but I gave the catalyst converter a good hit with a hammer and there didn’t seem to be any thing moving around in there