You're just unlucky. The taste issue is determined by genetics [1], although the grossest taste is often the result of sweeteners combined with aspartame, like

You're just unlucky. The taste issue is determined by genetics [1], although the grossest taste is often the result of sweeteners combined with aspartame, like Ace K. Sweetener mixes are made so that most people will not taste a gross aftertaste. Some people will experience a bitter aspartame taste, and others will experience a very chemical aftertaste for other sweeteners, but the majority of the market doesn't. [1]: https://academic.oup.com/chemse/article/38/5/379/360864 https://academic.oup.com/chemse/article/38/5/379/360864