This is a "gotcha" question and you know it. It's an either-or, all or nothing, black or white view of the papal crisis. Go read +Bellarmine's debates with John of St Thomas, Cajetan, etc. There's a lot of layers to all of this. It's very complex.
You still want to make this all about "theological opinions" and debates from the 1500s. That's wrong. The Code of Canon Law incorporated the essential elements of Bellarmine's and Cajetan's arguments. If you analyze Canon Law, you will find that both perspectives have their place at different stages of the heresy/excommunication process.
Bellarmine's position is primary. A public, manifest (
ipso facto) heretic, loses, by the law itself (
ipso jure),
his office without any declaration needed by any Church authority (Canon 188). The manifest, public heretic Pope loses his See, immediately from the perspective of the law. At that point, the person, who has "lost" (even if temporarily and merely
ipso jure) the Chair of Peter, can be judged by a Church tribunal, overcoming the limitation of Canon 1556.
Cajetan's position is secondary, but relevant to the entire process. The public manifest heretic is not finally "deposed" of "the office itself" until he is finally condemned/banned/
vitandus (Canon 2266). The process for this follows Titus 3:10-11 and can be found in outline in Canon 2314. But a person who has "lost" his Papal office because of
ipso facto heresy is excommunicated with a "minor excommunication"
latae sententiae.
Check the Canons I have referred to. Read Bellarmine and Cajetan with that in mind. You will see that both positions are in Canon Law in their rightful order.
https://cdn.restorethe54.com/media/pdf/1917-code-of-canon-law-english.pdf