Auto-Greenhorn seeks commuter vehicle

Dear experts, I’m afraid I’m starting to despair about the car question. Soon I’ll have to commute about 35,000 km a year because of my job, most of the route is motorway. At the moment I’m driving a small car with 60 hp (petrols) – in itself I’m very satisfied, but on the highway it’s quite a torture (I see the PS as problematic, but worse is actually the low weight) and I really want to increase myself. solid car (of course nobody can guarantee you something, bad luck can always be had), which does not always cause problems. I am already ready to have a diesel with more than 100 hp. From age I thought about 5 years and no more than 60,000 km. I have already looked at BMW 1 Series, VW Golf, Audi A3 (all as 5-doors). Audi is actually above my budget of 13,000 / 14,000 €. If someone has a hot tip for me, which car noc h could come into question or should one of my previous favorites rather be deleted? Thank you very much!