You also removed and reinstalled the Schrader valve, the most likely culprit in your leak.......
No, Do not have a Schrader valve?
I do have direct line to bag on both sides, single fill air lines for bags, simple set up. No compressor.
And yes replaced the lines, and 90 degree inlet, bench tested and water tested, with no bubbles.
Put bag (which was new), and replaced everything.
Sill leaked !!
Then I took every thing off again, and filled bag with SLIME and shook the hell out of it.
Put everything back on AGAIN-NO LEAKS
Bag has been holding at 20 lbs of air.
I would say the air bag is the culprit not lines or fittings.