ECAM 22.110 with barely any water coming through

When turning the machine on, it will run for VERY long, but the rinse is pretty slow, basically just drop by drop. When "brewing coffee", it will grind and sound normal, but barely any drops comes out of the nozzles (and they are clear). When turning on the steam wand for hot water, VERY few drops comes out. Same when I try to steam (sounds normal).
I assume it's a water issue.

When disconnecting the skinny white hose AFTER the pump and turning it on, water spews out just fine. Flowmeter seems fine. No bubbles in the water tank either.

I took out the two very skinny and white tubes (1 running from the heater and 1 further up) and cleaned them. Neither clogged nor dirty. When I turn on the steamer wand, the skinny hose from the heater will have some water running through it, but there seems to be air in it as well. I don't know if that's an issue? (Air would be needed to steam, so maybe not?)

The hose coming out from the side of the pressure relief valve in front of the heater and connecting to the expansion chamber is dry. I see absolutely no water in it, when I try to do a rinse, nor when I try to brew coffe, nor try to steam/run hot water. (When I disconnect the valve from the heater, a bit of water comes out of the heater, so THAT doesn't seem totally dry and not scaley either.)
I took apart the pressure relief valve, but I have no idea how it is supposed to look or work...

So, how can I tell if the PRV is the issue? Could it be the expansion chamber not drawing water in? Or is it supposed to shoot out from the PRV? How can I tell if the PRV is defective?

Thanks in advance!