The GoPro Hero 10 has three color profiles to coose from. The flat profile is particularly dedicated to those who use post-processing software to apply LUT filters, because it produces a result that is unattractive and not very natural. There is not much difference in color saturation between the vibrant and natural settings, rather it is the contrast curve that is accentuated in the vibrant setting.

Despite that vibrant is the default, consider to use the natural setting as the preferred one.