I am looking for someone to come in twice a week to help my father get a shower. Of course, would pay. I am just not comfortable doing it.

There are agencies out there. We cannot help you because this is an international group of caregivers offering advice. Check with your local social services or contact large elder homes and ask who their residents use to get started on this search

In my experience, some agencies will provide bathing assistance but it is very expensive. As AlvaDeer suggested, a private caregiver is your best bet. If your concern is one of modesty and your father is able to understand, there are ways around that, as opposed to being physically unable to help him.

This is something for you to explore online. While this isn't likely going to work for "most" agencies, as they often require minimums such as three days a week, four hours per day, it will work privately hiring from someplace such as care.com. You can also ask in your NextDoor app if some practicing CNA would have time to help with this.
People hesitate to take on short hour jobs for this reason: they often have their day broken in a way that they cannot do OTHER jobs that have more hours and the pay they need for survival.
Wish you luck finding someone in your area.