Big question is, what is causing it? Arthritis? Meniscus tear?
Also, consider running shoes. They should be in good condition and a proper balanced fit for your foot.
That said, I would take Your running shoes and go to a legitimate running store. In San Antonio, I prefer Fleetfeet.
Other less likely less causes would be back / nerve issues, medical conditions or exercise induced compartment syndrome where muscles are not receiving enough blood flow due to swelling.
I tend to obviously focus on the specific injury, but on the whole person as well for a proper return to activity with less chance of re injury.
Rarely, more severe or worrisome conditions could cause such.
Generally speaking, motion and strength far outweigh the problems of a weak knee.