There's definitely more room for discussion, but you may find this recent thread on the same topic interesting. It has answers by u/DerProfessor and myself on Spanish America, and by u/PartyMoses on North America, all worth checking out. They mention how in earlier colonial times native slavery did exist, but was over time replaced by African slavery at least in British America - in many colonial Spanish American regions working conditions for indigenous people would continue to resemble slavery.

Hope this helps!