Please help

First of all, you need to verify 3 things.
You need fuel pressure, compression and spark.
You need a gauge to check fuel pressure. Remove a plug and attach the wire and crank the motor to see for spark. Install a compression checker into the cylinder to check compression.

At this point you need to stop guessing and find out what you have lost here. You have spent way too much money already on parts that did not fix it.

Roy