After doing additional adjustments to the pressurestat I managed to have it stabilized on the green area.
It does seem that frothing is now easier with lowered steam power than before.
I also took another step - I found out the temperature in my fridge was not cold enough . I turned it colder and now the milk I use is a bit more cold than before. It seems this helps as well. I don't even use the trick to freeze the jug before frothing.

After a bit more practice I managed today to make something that finally looks like a well frothed milk. It's my best effort so far. It is still not as good as I wish it to be but definitely a major step ahead.
I hope that now all parameters are right and that all that is left is practice practice practice as suggested here.

Thanks for all recommendations and tips. more to come when I am finally able to create the sought after Latte Art!