Salary requirements for Law Enforcement presonnel (Texas)

I have read that there is an overtime exemption for law enforcement departments with less than 5 employees. Is the employer required to at least pay regular time after 40 hours or comp time after 40??
Im not sure I understand the purpose of overtime exemption in this case. It seems that after 40 hours I would be working for free and at no limit to how many hours after 40 my employer could force me to work without pay.

I have also read that there is a minimum yearly salary in order to claim an employee as a salaried employee. It appears that January 1, 2020 that minimum was raised from $455 per week to $684 per week or $35,568 per year. Does this apply to departments with less than 5 officers as well?

My employer states that I am salary at $33,500 until my probationary period is over and then ill be paid a salary of $34,000 per year. If I have read and understand this correctly, they are not in compliance as the minimum as of 1/1/2020 should be at least $35,568.

Can you please help to clarify this for me?
If not, who do I need to contact for clarification?

Thanks,
Mike Adams