How do I calculate a PCB antenna trace width?
The TI reference design should include a layout. My advice is to copy that layout exactly for your first iteration and test it. Pay special attention to preserving the spacing between the antenna poles and the reference planes alongside (but not beneath!) them.

If it works well enough, go with it (it likely will.) If not, hope is not lost. You can adjust things a bit (spacing and width) to get things right, as the TI appnote said. To do this in a structured way you will need to acquire a antenna design tool and develop the skillset to run it, or talk to the FAE at the chip vendor.

Worst case? Hire a consultant. Which might be your best case if you've never done this before and you have bosses breathing down your neck for schedule.