I have started studying and comparing the passages in revelations in particular in Geneva vs KJV for this very reason, curious as to what King James changed translation on

True.

https://www.apuritansmind.com/puritan-worship/the-geneva-bible/

James ascended the English throne in 1603. He wasted no time in ordering a new edition of the Bible in order to deny the common people the marginal notes they so valued in the Geneva Bible. That James I wasn’t going to have any marginal notes to annoy him and lead English citizens away from what he wanted them to think is a matter of public record. In an account corrected with his own hand dated February 10, 1604, he ordained: That a translation be made of the whole Bible, as consonant as can be to the original Hebrew and Greek; and this to be set out and printed without any marginal notes, and only to be used in all churches of England in time of divine service. James then set up rules that made it impossible for anyone involved in the project to make an honest translation, some of which follow:

1. The ordinary Bible read in the church, commonly called the Bishop’s Bible to be followed and as little altered as the truth of the original will permit. Or, since the common people preferred the Geneva Bible to the existing government publication, let’s see if we can slip a superseding government publication onto their bookshelves, altered as little as possible.
2. The old Ecclesiastical words to be kept, viz. the word “church” not to be translated “congregation,” etc. That is, if a word should be translated a certain way, let’s deliberately mistranslate it to make the people think God still belongs to the Anglican Church – exclusively.
3. No marginal notes at all to be affixed, but only for the explanation of the Hebrew or Greek words, which cannot without some circumlocution, so briefly and fitly be expressed in the text. James didn’t want those pesky marginal notes cropping up, not even once. That was fine for the common herd, but not for James’ own bishops. Many of their writings and sermons alluded to the Geneva Bible and its marginal notes decades after the King James Bible was published.

He wanted the margin notes gone.