Is it true that the Spanish Inquisition was not as brutal as we think it was? If so, what evidence/data do we have to assess how bad it was, and how did it compare to courts of its time period in other parts of Europe?

I know this is not a perfect match, sorry. But if you're interested--I have an earlier answer on the historiography of the Spanish Inquisition critiquing an article that called the Spanish Inquisition responsible for shaping the modern world/Spain.

(It only baaarely touches on parallels with Protestant territories, though, and doesn't even explore the Church/civil authority difference there, sorry.)