Best way to travel from Kerpan/ Düsseldorf to Salzburg with limited time?

Hello

I will be leaving Kerpen at 16:00 on a Thursday but I need to be at a city near Salzburg before 9:00am Friday,

What’s the best way to travel from kerpen to Salzburg?

From Google I thought it will be kerpen to Düsseldorf airport on Thursday evening then flight either to Munich or Vienna and get a train from there and hopefully will arrive at a hotel before 10pm Thursday night?

Is this the best way?

I do not want to hire a car if possible.

Thank you.