1. There's no thing such as block size limit, Bitcoin now use block weight and block weight limit.
2. Double-spend is still possible even without RBF implementation. You can make 2 different transaction with different output and same input, then broadcast to 2 different nodes.
3. You can't use RBF to change the output, see "First-seen-safe RBF" for more info.
4. With that video's author logic, even meme coin such as DOGE is better than BTC and Bcash.
I do think that it's a plan to attract bigger public towards the Bitcoins cash 😂 whoever made this video was getting frustrated with the Decreasing value of Bitcoins cash.