With at least one adjustable, dialing it up to 5 actually gives a worse result than 3.5. I think this might have something to do with the blade not having enough support, so it's flexing/vibrating more due to the greater blade gap
My whiskers aren’t white yet, but they are very thick/coarse. I’ve always had much better luck and gotten better shaves from razors that clamp down very securely near the cutting edge of the blade. The Fatip Piccolo on the inexpensive side and the Timeless titanium or Lambda Athena on the expensive side are examples of razors I’ve used that clamp well and shave very smooth for me.
Another thing that might help is the bullfrog technique. It’s basically the opposite of pulling your skin tight. I get better results under my chin on the xtg pass by pointing my chin downwards, causing the skin to kind of puff out.