Why won't my flute play?- Learning to repair

[flute444]

Hi friends. I messing around on an old flute so this will not be going to the shop- I am learning how to repair.

I have repadded the instrument and I am still having issues with leaks, low octave f# and below. When I press the keys really hard it plays completely fine. I have messed with adjustment screws, played around with shims, and have even tried bending the keys the slightest amount(watched a repair tech on youtube). It has definitely gotten better, but I dont know what else to do. Thanks!

[flute444]

update: it sometimes plays for a minute and then stops sounding clear. nothing appears to be shifting around...