Express keys on Gaomon PD1561 Tablet not working in Photoshop CC 2019

I'm using a Gaomon PD1561 Drawing Tablet in Photoshop CC 2019 on Windows 10 and my express keys won't work in Photoshop. They work in other apps fine but in Photoshop they don't do anything. The shortcuts for each express key are basic ones like B for the brush tool or the brackets for changing brush size. When I press the buttons in apps like Microsoft word or my browser, those letters/symbols show up, but if I press the buttons in Photoshop nothing happens. I have the latest driver installed, the pen writes fine, everything else works normally but the express keys do not register in CC 2019.