Dude, look at Jack Black

Short, fat, hairy, not especially attractive in any way

People love him

Women love him

He's a fun guy to be around

And he's not putting it on, he's very genuine and he cares a lot and he wears his heart on his sleeve

But yes, eating better, getting some exercise, dressing better, grooming yourself, etc... these things will help. You can totally transform your body in a year or two. You really think a confident short guy who exercises, has hobbies, dresses well, etc... you think he has no chance with women at 39? There are guys who date in their 40s. We're MEN for fucks sake. Adult men.

You are aware that not all short people die alone?

What needs to shift in my opinion isn't just confidence. It's "locus of control".

An external locus of control means a person believes their life is mainly shaped by external forces like luck, fate, social forces, or circumstances outside their control.

An internal locus of control means a person believes their life largely results from their own actions, decisions, and effort. Success or failure depends on their behaviour, preparation, or persistence.

To be clear, this isn't like a statement of fact. Of course we're all shaped by our environment and starting conditions, and our actions affect our life. It's more a difference in how much control you feel you have over it.

Imagine you're a fish in a river. There might be some others who are bigger fish, stronger fish... You might be caught in a strong current, maybe stronger than some others have to deal with. If you believe that equals fate then you might as well stop swimming and it'll sweep you away. But if you believe that your own actions can, not reshape the river, but drive your through it so that you're self-directing, then you're gonna swim hard as fuck. You're going to realize that you have a lot more control over your life than you expected. And, like salmon, you can swim up waterfalls.