Pre-COVID -- when I worked in Slovenia I would often stay in Zagreb -- my usual entry points to the area if Zagreb flights were too expensive / bad timings were LJU and GRZ -- almost always on LH via FRA / MUC. Post COVID I would look for LX flights all day long -- or flights via MUC if they still exist.... Of course back then we had a car service that would pick us up at any of those airports (the drive isn't as bad as you think).... And back then -- it seemed that LH were the only ones to have early morning return flights -- (which you need to get back to the US at a decent hour.... And all the others were always in and out - so later departures in morning...