It works now !
That could have been due to my crappy internet connection (im am located in digitally underdevelopped Germany).
Oh yes, WiFiTimeout should be in one word, of course !
So now i can standardize my device configuration too.
You create at thinger.io your device, create a “setup” property and have all your operative parameters there, instead of hard-flashing them in the code.
Combined with the PythonFlasher to patch the credentials, I can now distribute binaries that must not be compiled by the user.
With the huge advantage, that you can change the parameters right from Thinger and just reboot !