Welcome to the world of autobahn driving.
I think it is as bad this year as it has been in previous years, maybe worse.
I'm just completing a circuit around southeastern Germany, Belgium to Wuppertal (yay, what a hoot!! - everybody should have a go on the Schwebebahn) to east of Frankfurt to the Mittelrhein to Wurzburg to the Romantic road to Augsburg to Munich to Luxembourg via Stuttgart.
I've put in a fair few clicks on the old odometer.
Consistently, all along the German parts of the route, it is very short bursts of 150 kph followed almost immediately by several km at 80 or 60 kph through the construction (watch out for the radar cameras) before another quick burst.
Don't count on google maps - they can be optimistic.
Just go with the flow.
Coming off the Mittelrhein towards the Frankfurt conurbation expect delays. The route through Ruedesheim is very slow, and the route across the Main into Mainz is very slow because it is very narrow - you have to go through a narrow and low gauge tester that whacked one wing mirror the other day before you get on the bridge. It is restricted to only cars and small vans that can get through the tester. Otherwise you are going many km out of your way, with all the heavy vehicles.