Shoe left/right color difference

[Silvaro]

Have bought a secondhand pair with a problem I try to find a solution for.

Using the color palette names on https://www.researchgate.net/figure/The-seven-shoe-components-and-corresponding-color-palettes-used-in-the-NIKEiD_fig1_232409410

- 1 shoe appears to me as "linen", I'd describe it as the same of a typical western cowboy hat

- the other is kinda brown - alot darker.

It's clear that some1 did something to the second (brown) one, since the belt still is the same lighter color as the other one.

Likely the sole solution avail is to bring the "linen" one to the darker brown one. But how?

I tried some brown and neutral/wetter polishes / smears but they didn't make (lasting) difference.

Material is leather.