Hardly any milk foam Caffeo Barista TS

Hi guys,
I have now read here quite a bit to the milk foam, but to the above machine still nothing found. My problem is that the machine no longer makes a proper milk foam, but virtually only hot milk comes out.

What can I do?
I have decalcified twice now with "good" decalcifier and that has not helped.
What are my options, since I'm not really the king of craftsmanship and as I understood the disassembly video the drain valve (?) is not exactly the most uncomplicated.

* Does replacing the hose do anything? When I blow through it, it doesn't appear to be leaking.
* Does it help to replace the intake nozzle? (Isn't that the removable rubber part?) I have cleaned and blown through it several times -> no effect*
What else can I do?

Many thanks already

I am in the same boat and would appreciate any advice.