Ya’ll know the big feet / big hands thing is bullshit, right?

https://factbasedurology.com/penis-size/shoe-size-link/

The set of genes at play with those things is totally unrelated to dick size, there’s no correlation, no causal mechanism.

The only thing that even barely correlates is just your height, and its a very weak correlation.

… The overcompensating via a large/flashy/expensive car thing though?

Well, there’s a very well established phenomenon of male insecurity re their dick size, and overcompensating is a well established psychological phenomenon.

Very plausible, but I’m not aware of any studies that have actually been done on exactly that.

(As a bonus: studies also show that women are generally fairly bad at estimating the actual size of a dick, and are generally abysmal at guessing how common dicks of whichever size actually are… though most men are also pretty bad at that last part too.)

The main thing that a guy can do to… not actually have a bigger dick, but appear to…

Is work off belly flab and pubic area fat.

Mt Rainier is not the tallest mountain in the contiguous US, but it is the most prominent, ie, tallest compared to what surrounds it.