This came up because of the interesting Taylor DeSoto Youtube.
Good talk, many interesting points. Servertus, who was at Valladolid in 1527 as a teenager, secretary to Juan de Quintana, accepted the heavenly witnesses verse as scripture. Grantley McDonald in: Raising the Ghost of Arius p. 152-154 https://openaccess.leidenuniv.nl/handle/1887/16486 seems to be ok in that section and gives Latin paragraphs. (You imply Servetus as a contra at 8:50.) Offhand, I do not know of Erasmus-Servetus correspondence. Good info here on Erasmus and Servetus, p. 36-39, should be visible. Encounters with a Radical Erasmus: Erasmus' Work as a Source of Radical Thought in Early Modern Europe (2008) Peter G. Bietenholz https://books.google.com/books?id=1cxY0mm2ZwMC&pg=PA36