Right now, the only toggle under Touch sensitivity in the submenu is the Screen protector mode which, when toggled on, “will increase touch sensitivity and improve touch when using a screen protector.” To get there, go to Settings > Display > Touch sensitivity.
The new adaptive touch feature could have a toggle located in the new Touch sensitivity submenu
When the new feature arrives, besides allowing a Pixel user to use his finger on a wet screen and still employ it as a touch input, the feature might also work to allow a finger to tap buttons and more during extremely cold weather. It should also allow the user to navigate the touchscreen using his finger while swimming although we wouldn’t recommend that a Pixel user go for a swim with his phone even with its IP68 dust and water resistance rating.