Remember that’s a big air bubble coming out of a very small bleeder screw so for it squirt then nothing then squirt again is normal when there’s air in the system. But still check the tstat. Check the coolant elbows too make sure nothing is coming out of there. The passenger floor has coolant on it then your heater core went.

I usually have the heat on to help get wire out of the heater core too when I’m burping.