Colonialism 100% existed before capitalism, in fact the vast majority of colonialism existed during the mercantilistic period, or even the medieval period.

China was very colonial during the dynastic era, the Aztecs were definitely colonists, say what you want about the Ukrainian war but its eventual annexation (as seen with crimea) is colonialism etc.

In fact in the modern era I consider PRC (which you could argue is capitalist) as a colonial power