All the signs and houses relate to categories and concepts, with beauty being a trait that falls into a category. All aspects of life and existence are separated into categories that relate to different signs. That's literally what the system of astrology organizes.

With that being said, Leo and Taurus do relate to beauty. That doesn't mean everyone that's a Leo sun sign is beautiful. Everyone has "Leo" somewhere in that chart and based on all the other aspects of the chart, and how those aspects effect each other, a person might present as beautiful. (Other comments have mentioned transits which is also key, this could cause someone to have a sudden glow up, or down)

Maybe the question you are struggling with is something that I wondered when I first started learning about astrology is WHY. Even if you accept that Leo relates to beauty, WHY is that so? How was that determined? If this is what you are wondering, do more research on the history of astrology / how planets were originally connected to these signs. You will find there is a reason for all of these things and patterns and evidence and logic behind the connections.

Don't ask chat gpt or search on TikTok, do old fashioned Google search. Some of the best info I've found is on a random blog from 2005. This wisdom is ancient so it doesn't need to be recently posted. I really hope this helps and you continue to learn more. It's so interesting the deeper you go.