Being confused

At first m thinking of visiting Bangkok city during the transit , but now m a bit hesitate.
if i take the tour to visit bangkok , i will leave phnom penh at 8 AM . it is a bit early. and i have to take lunch n dinner alone in Bangkok. it might be good to have lunch with family in cambodia.
so i might change my flight schedule from departing phnom penh at 8AM to 4PM.