Neo-Brutalism is an accurate way to describe GumRoad's design, but not the OP.
Neobrutalism adds color and bold design to brutalism, but maintains the simple focus on structure and function. NB features prominent and simple shapes to delimit UI elements and buttons, and bold and prominent typography.
NB is not "Retro" nor "cyberpunk", and it doesn't add in superfluous details and decorative elements. You wouldn't use Emoji in NB when a simple bit of plaintext would do.
Good for the OP for working hard to create something very fun and unique, but it is not Brutalism nor NeoBrutalism.
Neobrutalism adds color and bold design to brutalism, but maintains the simple focus on structure and function. NB features prominent and simple shapes to delimit UI elements and buttons, and bold and prominent typography.
NB is not "Retro" nor "cyberpunk", and it doesn't add in superfluous details and decorative elements. You wouldn't use Emoji in NB when a simple bit of plaintext would do.
Good for the OP for working hard to create something very fun and unique, but it is not Brutalism nor NeoBrutalism.