I know EON has a controlling stake. I mentioned it in my post you quoted.
Amazon has the money MGM never dreamed of to throw at that family and tbh, unless they are EXTREMELY principled and just don’t want to make a deal with Amazon under any circumstances, then Amazon doesn’t have much to worry about long term.
And tbh, they may not even purchase MGM if they can’t get an assurance from EON that they’ll be willing to work together on Bond projects going forward. It’s been rumored that they want No Time To Die to be the last Bond film.