Thank you for your answers!
It worked but it was a bit harder than I thought.
It was 3 wars actually to vassal Bohemia.
Than Austria has the final laughter because of my large infamy.
Reload->Burn infamy for years->vassal Bohemia->hre
It was basically bad luck because I managed to vassal the 4 electors just after the young Bohemian king was elected to hre.
So I have to do the hard or long way.
I can choose to wait 20-30-40? years the HR emperor to die or wage 3 wars to vassalize his country...
Nevertheless I got HRE in 1465 with England.
It worked but it was a bit harder than I thought.
It was 3 wars actually to vassal Bohemia.
Than Austria has the final laughter because of my large infamy.
Reload->Burn infamy for years->vassal Bohemia->hre
It was basically bad luck because I managed to vassal the 4 electors just after the young Bohemian king was elected to hre.
So I have to do the hard or long way.
I can choose to wait 20-30-40? years the HR emperor to die or wage 3 wars to vassalize his country...
Nevertheless I got HRE in 1465 with England.