A word for someone who uses their sex appeal to get a job/success in life or who has a job and stays in the job just because of their good looks

Solution 1:

Eye-candy (also eye candy) may be what you are looking for.

Collins:

eye candy also eye-candy
uncountable noun
Eye candy is used to refer to people or things that are attractive to look at but are not interesting in other ways.
[informal]
Back then, women on TV were mostly seen as eye candy.

COBUILD Advanced English Dictionary. Copyright © HarperCollins Publishers

eye candy
noun informal

2. something intended to be attractive to the eye without being demanding or contributing anything essential

Collins English Dictionary. Copyright © HarperCollins Publishers

dictionary.com:

eye candy
noun
1. Slang. someone or something that is visually attractive or pleasing but is usually considered to lack worth or merit.