Brakes. Gods revenge on jeepers. I have had a few go arounds with my power brakes. Here's what I would do. Take the MC off, you can leave the lones connected, and have someone push on the beake pedal. See if the rod is actually moving. Next If the rod is moving out, I'd put the MC back in place and unhook one brake line and hook your MC bleeder fitting back in and see if fluid comes out when the pedal is pushed. And you did bench bleed the MC I assume before installing.
FWIW if you do not already know, you can gain some pedal by adjusting the fitting on thre rear of the booster where the pedal connects.
Pull my finger