I would also like to mention that whatever javascript code that those websites use literally disable the opening of the options menu when you click it somehow

Hey Everyone, I opened a key testing website (https://keyboard-test.space/) in the PS5 Internet Browser via messages and found out that for some reason, Some of the controllers buttons are registered as function keys. Here is the Table I made of all the buttons that work.

D-PAD: Arrow Keys
Triangle: F1
Circle: ESC
Cross: Click
Square: F2
Left Stick: Mouse
Right Stick: Mouse Wheel
L3: F9
R3: F10
L2: F7
R2: F8
L1: F5
R1: F6
F3: OPTIONS
Unbindable as of 29 April: Touchpad, Touchpad Tap/Click, Mute Button, PS Button, CREATE Button.

If you test this out via the link it should work. This could be really cool and useful for games on the PS5 Internet Browser