1999 5.3 cranks but has no spark

I need some help from anyone who knows these engines. From what I can see everything is hooked up correctly but obviously something is wrong…. I have spent 2 days trying but can’t figure it out.

Modified factory wiring harness and computer

Generic wiring harness and fuse box

Th400 transmission pre computer

Absolutely no factory wiring left to reference.

How are the ground wires? Is the vats turned off in the computer?

I have 3 grounds from the harness grounded to the block. 2 of those are also grounded to the firewall and the other to the frame. I also have the battery grounded to the block and frame plus 2 more grounded from the engine to the block. I have tested ground in both coil grounds and they are good. As far as the computer it was sent in and modified so should be all set but I don’t know how to verify this. I’m going to pull the crank sensor this morning to test but otherwise I am baffled. This thing should have fired up 2 days ago…. It’s getting frustrating to say the least.
Also, I am not showing any codes but all I have is a basic code reader