Apple seems not to have solution for ill-fitting size L AirPods PRO ear tips. Not large enough. HELP!

Apple only manufactures the 3 sizes of tip supplied with AirPods, and it would be unusual for one of the choices not to fit. I suggest you experiment some more to be certain (it might need some patience and a mirror), and leave your comments in Apple's feedback system if you still can't get an acceptable fit. https://www.apple.com/feedback/

Hello ~ I had the same problem and shopped for a set that also included ear hooks. Good fit now and much less worry about losing and not being able to hear properly. There are lots of choices in white (or colors…if you like) and you are still able to tell they are AirPods for sure. Good luck and enjoy your AirPod Pros

~Katana-San~