KR 721 then TG 407 at Bangkok
Siem Reap → Bangkok → Singapore
Timetable, Bangkok time
17:05KR 721 from Siem Reap at the gate
14:40TG 407 to Singapore leaves the gate
21 h 35 apart on the timetable, overnight
TG 407 leaves 21 h 35 after KR 721 arrives on the timetable: more than half a day, so not a connection we count.