Paper products like Posters and Cards will display brighter colors but it won’t be a 100% match. Direct-to-Garment products will absorb a larger portion of the ink and will print more muted colors. However, products that are printed using sublimation will display bright colors pretty well!
Here is a list of products that are printed under each system:
Long story short: products are printed using different methods and inks. There will always be color variations between each product and there may even be very slight color variations on the same product printed on different days.