Jagex claims to “share” your personal data to advertisers like Google without getting any “monetary” benefit. For Free! What great friendships these corporate entities must have.
You can opt out with this link here, just be careful not to accidentally delete your account (unless…?):
https://support.runescape.com/hc/en-gb/articles/360001370829
The Opt Out works for all UK and EU members, but if you live in the USA and Brazil there are some extra requirements such as living in Virginia or California for the USA. You can do this by entering your ZIP Code on the form. The California Zip Code, which you live in, Capische?
Got some error when using their form to opt out
Did you submit a support ticket? Maybe try a different browser.