What should be avoided is the hype about him being an American or even sillier by some low information Catholic Bishops , is that he was a Founder of America.
The most accurate history shows that he was a citizen of Spain assigned to establish missions in New Spain. He was a contemporary of George Washington and gathered donations for the Revolutionary war for unknown motives, but could have been from dislike for England.
Serra wasn’t a Citizen—Citizens take part in their government in someway—Serra was a Subject of the Spanish King. His goal—to save the Indians souls for the Roman Church and reduce them to peons (serfs—not slaves) for the greater glory of the Spanish Empire and the King in Madrid. Many of the natives died of disease but that was not part of the plan—they tried all they could to save them. But 75% of the Native Population died.