How can I give up POA and make my dad a ward of the state in Texas?

If you wish to give up your POA then it is DIFFERENT in the case of an INcompetent person compared to a competent person. If a competent person gave you POA you could simply write a resignation letter to that person, and then go to each entity where you are registered as his or her POA and let them know you are no longer acting as POA for the person.

In your Dad's case it is more complicated. You have taken on the POA and now he is no longer competent to appoint another. In many states you can call APS and they will assist you in resigning your POA, but in some they cannot/will not and you will then need an attorney as it is a court action. The attorney will guide you through resigning as POA. Then they will have the court appoint a Fiduciary to act for the state in guardianship.

Good luck as you move forward.

There’s so many only daughters that feel caregiving is automatically their duty. It isn’t.

First… get your job back or get a new one ASAP!

https://www.agingcare.com/articles/can-a-caregiver-change-a-loved-ones-power-of-attorney-137706.htm#:~:text=While%20each%20state%20has%20different,mail%20with%20return%20receipt%20requested.

After you resign, call APS and report him as a vulnerable adult. Depending on the state/county the process will take a while. Once the county has guardianship, you won't have any insight or access to any of his financial or medical affairs but wherever they place him you will have all the ability to visit him as his daughter.

An immediate solution to the soiling problem: purchase "anti-strip" jumpsuits from silverts.com so that he cannot access his disposable brief without your help in getting his outfit off.

Would he go to the hospital if you call an ambulance? When was the last time he had medical care?
it will be easier to get him in a facility if he goes from a hospital. I think I would call an ambulance and have him taken to an ER and see if they can place him in a NH.
Only sign anything you are asked to sign as agent of his POA. Has he been diagnosed with a dementia in the past?

A poa doesn’t mean you have to do care, it means a say so in how that care is administered. I would contact your area on aging or aps and say dad cannot stay in independent living as he soils himself, there is no money for more, and you cannot provide.