We arrived 23 Feb, was at Embassy 24 at 9am (application 9-10 only). Because of the weekend we were asked to return today 28 between 3-4pm.
No problems getting PCR, go to Intercare/Olympic medical, open 7 days and holidays. Test before 9.30am, results same day collect at 5-6pm. Test after 9.30am, results next day 12 noon. Cost is $130. There is a cheaper option at another facility called Pasteur but 3 week waiting list currently at $80.
So 7 days for us total, but you could do it quicker, say if you arrive Sunday, go embassy Monday, collect Wednesday and get last flight out (4 days).
We did 7 days as we have an appointment with UK embassy in Bangkok March 3, so had to fit that in with quarantine considered.
Can I point out that Thai Embassy in Cambodia insist flight out must be within 60 days of arrival, I contacted them by email and then in person at the Embassy. I am trying to gather as much information as possible so I can make a post on our experience.
3 working days including application day and pick up day. The only way you can do a return quicker is return without a visa. If you want to do it this quick, look for Intercare who do same day PCR test if you test before 9.30am, $130. You could possibly just come in and leave on next flight, using your original PCR test.