Hi Nico
While I'm no expert it would appear that your flame is way
Too rich . 1st ,to start if you replaced that tee fitting with a cross fitting that would double the air flow, 2nd, move the gas jet back to where you can see it through tee/cross it will draw more air. 3rd, that orange euro gas hose should be replaced with metal/copper the hose is ok to test with tho.that should get you closer to start with.
Cheers Ken