In case nobody did this recently, did you already check the Embassy website? Quite good information and not too old (2022).
https://phnompenh.thaiembassy.org/en/publicservice/non-immigrant-o-visa-thai-family?page=5d73b14415e39c46f40076a1&menu=5d73b14415e39c46f40076a2
Visa application times
Open Monday to Friday, except Embassy holidays.
09:00–11:00 AM document submission (no appointment required)
03:00–04:00 PM visa collection
Visa processing times (NOT including day of submission)*
3 working days (NOT include the Day of Submission) for Tourist visas, Non-Immigrant Labour visas for Cambodian migrant workers (for example, if you apply on Monday, you can pick up your passport on Thursday)
5 working days (NOT include the Day of Submission) for other Non-Immigrant visas (for example, if you apply on Monday, you can pick up your passport on the next Monday)