Texture file size tells nothing about the resolution, or quality. You can make a game with a single 4096x4096 texture, which contains the terrain, soldiers, vehicles, skybox, etc… and you can do a single decal in game with 4k texture.

Ive used single 4096x4096 texure 14 years ago for my locomotive DLC’s external model, to optimize drawcall count. And another 4096 for the interior model