A "rematch" doesnt signfy anything on you think the outcome is. It doesnt signify it will happen anywhere outside of also involving Luffy. It also doesnt even signify that YOU, the reader, will get anything out of it.
Oda will never be able to justify this fight. This is why it took multiple Blackbeard commanders to fight Garp while he was handicapped, and THAT took 4 chapters alone. You expect Blackbeard to get a full, onscreen fight and it be fully justified against 10 RHP members, who are considered the strongest crew by their numbers? All while hiding fights for Luffy and any of it to be a surprise for the story?
I guarantee you it wont pan out the way you are expecting it to.