GQ 681 then LX 1839 at Athens
Sofia → Athens → Zurich
Timetable, Athens time
21:55GQ 681 from Sofia at the gate
17:40LX 1839 to Zurich leaves the gate
19 h 45 apart on the timetable, overnight
LX 1839 leaves 19 h 45 after GQ 681 arrives on the timetable: more than half a day, so not a connection we count.