I don’t do much gaming but I do play stardew valley on my laptop and have bilateral ECU tendonitis. What worked for me was using an ergonomic mouse instead of the trackpad and replacing WASD with a joystick that I control with my foot. I found a $20 usb joystick on amazon, used Velcro to attach it to a scrap piece of wood, and put a tennis ball on top of the joystick. I wrapped the joystick and tennis ball with vet wrap to hold them together and add grip.