There really should be a stronger setting if the controller can go that much. 10 isn't enough.
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Sorry its a hardware limitation! There isn't anything I can do about it unfortunately.
I am not sure which gamepad you are using, but I have found from my experience that my PS4 gamepads were much stronger than my (non Bluetooth ) Xbox One gamepad. And the least strong was a non genuine wired Xbox 360 gamepad I bought off eBay over 10 years ago.
So it's possible that maybe if you have a non genuine gamepad like the Madcatz ones etc., that they may have better vibration. But I also have no idea if those would work either.