Can you please tell me more about this opt-in RBF if you have links please share how does it work. Is there a post as regards this if available share link
There are many sources if you search with the keyword "opt-in RBF" through search engines. Basically, it allows you to replace your transaction with a new transaction with a different fee. You can also scroll around this forum since some topics do discuss it like this one[1].
[1]
https://bitcointalk.org/index.php?topic=5265729.0