Soft pedal first push

Don't be insulted if I say something basic you know by heart.

Bleeding technique is important. I work the bleeder back and forth between tiny bubbles sucking air around the seat versus actual bleeding, while I keep squeezing the hand pump to keep a vacuum on the jar.

Are you driving to check? Loose wheel bearings act like extra runout in the rotors, pushing the pistons back more in the calipers so there is more travel to take up when the pedal is pressed initially. I would not expect a second pump right behind the first to go as far.

Can't see how it is but the truck/van master rear port is for the front brakes like most masters.

New (china?) master may not be as good as it should be for the bore and seal, but then it would leak down/not hold. Looks like you ran hard line and just replaced the flex with stainless so that's good. I assume no vertical loops to trap air.