Hello Bjørn,
I have exactly the same car but with no problems. When I bought it, it was not smooth at motorway speeds, but as the mileage built up, it cleaned and it runs with no problems.
For your case, as you cleaned the EGR before and you had some success, why not try to do it again?
For best results, you must remove it but there are also sprays that you use in the air intake or fuel additives.
The manual does not recommend to use any fuel additives but if you cannot remove it and clean it again, that may be a good option for you.
You have already ran the diagnostics and you have no error codes, so the EGR clean up may work again.