Function of pressure regulating valve or control gear in the AFN

Hello fellow enthusiasts,

While trying to find the cause of the increased oil consumption in my car (approximately 0.3 to 0.4 liters per 100 km), I've now reached the flat, round container on the valve cover.
The part is called a 'pressure control valve' by Audi. What pressure does it regulate?
Even after an extensive search using the search function , the true function remained hidden from me.

How is this supposed to work in order for it to be okay?

The two connections (from the valve cover and from the crankcase) appear to be equivalent.
It seems that the connection to the ATL can apparently be closed off using a membrane (with a valve).

In my modified version, all three connections are linked together. It's possible to blow air through them.
Therefore, the ATL would suck in everything that comes out of the crankcase. That somehow makes sense...

If I strongly draw fluid into the connection for the ATL (hmm, delicious fully synthetic oil...), and then close the other two connections, the membrane valve will seal that port, allowing you to reopen the other connections.

Is this a feature or a bug?
Normally, there is only a very slight vacuum inside this hose, while a larger volume is available on the crankcase side, so it should never be able to close off completely, right?

Of course, you could simply buy the thing from a dealer (but first, perform the 'suction test' at the parts counter and, if necessary, return it ).
But most likely, this part will cost at least 20 euros again, which is money you don't have to spend if everything were okay.

Best regards,
K. Oldewurtel