If I’m not wrong, to enable custom CSS on individual game pages you would need to contact support to enable that for you. I’m not sure if the same procedure is needed for the creator’s page (where the community profile link appears), but I would imagine it is.
One word of caution: The default appearance is tailored to have a different look on desktop and mobile. A small change like making a button bigger might seem simple, but might break how the page looks on different screens. Usually making an element invisible (in this case the community profile link) shouldn’t cause any issue, but it’s worth keeping that in mind.