Heat doesn’t alter flavor. Capsaicin itself is flavorless, so if you just take a food and add capsaicin extract, it’ll increase the heat without changing flavor.
However, IMO there’s no point in doing that unless you’re trying to win a challenge. Most of us get capsaicin from peppers, and each pepper has a unique flavor that can add a lot of nuance to a dish.
Plus, I enjoy the heat sensation and am highly tolerant, so I can eat high heat foods and enjoy them. I would not recommend a spice-naive person start out on super hots.