Thank you all for your answers!
That was just an theoretical calculation. At that time, I was not aware that also the number of transmissions are regulated at TTN, thats now my biggest problem
thank you for that hint! I will check again the regulation!
You are right, I dont need the seperators in the end. I will recalculate it and change my code to SF7 125kHz. Lets see if I can stay into the borders of EU regulation “Worst” case for me would be to set up an own Gateway.