Sounds like a couple issues going on here. Let's start with what sounds like the most immediate which is the not starting.
Your engine needs three things to start. Ignition/spark at the right time, fuel, and compression. The backfiring sounds like a timing issue so we need to start with spark. I assume you have spark due to the backfiring but not at the right time. It also appears you have fuel because using the fuel in the intake did not make a difference. Let's assume for now that nothing happened to the compression as this seems to have just started. However, a compression test could show a timing issue if it is out far enough.
This means we need to tackle the timing first. This means we need to check for codes and see what is there. I am not suggesting that timing is off due to it being a timing chain and not a belt. Plus nothing seemed to happen to cause this.
I am thinking there is a variable timing issue. If this is the case there will be codes. Which is why we need to start with codes.
Here are guides that will help get this process started:
https://www.2carpros.com/articles/how-camshaft-variable-valve-timing-works
https://www.2carpros.com/articles/car-cranks-but-wont-start
https://www.2carpros.com/articles/engine-surges
Lastly I attached the info about the cam position sensor because it could be as simple as a sensor or more complicated like a cam phaser.
Let me know codes and we can go from there. Thanks
Images (Click to make bigger)
Wednesday, April 1st, 2020 AT 7:03 PM