Looks are like the packaging of a product. Personality is the actual quality/usefulness of the product.
If a product’s packaging is shabby and does not clearly convey what to expect, people are less likely to pick it up in the first place. A great-functioning product can be missed because of bad packaging. So looks are also important. But they are mostly for first impressions and getting someone’s attention.
However, after a product is picked up, the user expects a positive experience. And if the product doesn’t have innate value, or doesn’t live up to what was promised, or has quality issues, then that hurts a different way - and people give negative reviews etc. That’s where personality comes in. It is more long-term, and ultimately determines the overall fulfilment you can get with someone’s company.
Anyone who claims only one or the other is important doesn’t fully understand human relationships.
About looks, you cannot fully change your genetics or base body type. But you can definitely fully dress smart, be well groomed, and play to your strengths to make a good impression. Similarly, if you feel your personality is lacking, it can also be intentionally improved to attract the kind of people you want to have around you.
Life can be tough, but we are less helpless than most of us would like to believe.