California- is my employer screwing me on overtime?

I am a security guard that works at an apartment complex in San Diego county CA.

It is a very quiet chill job and all I do is sit in my car. And watch who comes in and comes out. And respond to noise complaints. Nothing ever happens here and I’m basically paid to sit in my car and watch movies on my phone. My hours are Weds-fri 5pm-10 pm (5 hours) And Sat-Sun 6pm-4 am (10 hrs) totaling 35 hours a week. Now I know this is under 40 hrs a week but on the weekends it’s a 10 hour shift. I think I heard something about in California working over 8 hours in a day is overtime. If that is true that I am entitled to 2 hours of overtime a day. 4 hours a week 8 hours per pay period. Yesterday. My coworker who I referred a little over 3 months ago worked 3 shifts 9 hours and 1 shift 11 hours. When he brought up to our supervisor/operations manager about working over 8 hours and making sure he’s paid overtime. Our supervisor got real argumentative over the phone and claiming he knows nothing about overtime laws and the company’s third party Certified public accountant does payroll. The next day (today) after working 10 hours on the weekends for the past 6 months. My schedule was adjusted for 8 hours on the weekends. I’d like to get everyone’s thoughts and opinions on this matter. And let me know if you think or know I’m owed overtime. Thanks.