And yet cuм ex specifically refers to the possible event of a Roman Pontiff falling into heresy. Notice the words...."Roman Pontiff." That means the Pope.
Notice the words "promotion" or "elevation"
Notice the words "no authority"
You literally can't deny what cuм Ex Apostolatus was saying. It is well-known and widely accepted that Pope Paul IV wanted to prevent a cardinal he suspected of heresy from becoming the next Pope.
Stop lying to yourself.