Brake pedal goes to floor.......pads, rotors and calibers are new, lines have been bled.

Booster diaphragm is bad .

Brake line busted somewhere? Is the linkage to the master cylinder intact? Master cylinder might have been installed incorrectly.

I would go with not bled correctly

The booster should hold up with a hard pedal until
you start the engine, then vacuum causes it to move
down when pressing on the brake

probably you have to bleed the master .couse seem to me till air on the brake lines

yes may need to bleed lines at master cylnder

Are the rotors worn? Worn rotors and new pads will sometimes cause this. The pad sits across the ridges and no matter how much you bleed the system the pedal just wont stiffen up. (See diagram. A - New pads, B - Rotor, C - Ridge)
If you did not install new pads you may also want to check the master cylinder seals. First bleed the system at the pipes that connect to the master. If the rotors are ok, you've bled the master cylinder and the problem persists then replace the seals or the complete master cylinder.

your power brake booster is blown out
the seal has a leak in it
run the truck for 3 minutes and shut it off. with the windows up listen carefully while you gently apply the brakes
listen for a hissing sound of air leaking.
the sound of these leaking is a very soft sound

Hi:
If you have replaced all pads, and see no leaks at any wheel, and have bled your brake system, then most likely your brake master cylinder has failed.

may be bad caliper could be why pad went to metal/metal

You may have a leak in the booster or master cylinder. You can put a pressure tester on the system to test for leaks. It does sound like you have an air leak.
You can try to bleed the master cylinder, then slave cylinder, then brake lines.