I have always experienced good results if i slowly flush/bleed the brakes with engine running. I place a 2x4 for preventing full pedal travel too or the piston seals may get damaged as they move into corroded zone

If you test with no vacuum assist you will never get a satisfactory result. I would suggest you bleed it again but place the catch jar/bottle above the bleed bolt level to prevent air being backed into the bleeder when the pedal is released. Parts stores sell a one man bleeder that has a magnet on the catch bottle to stick to the car for easy work.

Hopefully your problem will be solved otherwise a replacement MC would be required

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)