Personally, I don't think you adapt quickly enough. Seemed like you just played the same game regardless of whatever I did, and didn't react to counter things being done.
I agree with Zeron, you really should not be doing any kind of sandbagging against someone better than you. Not if you ever want to play them again anyway.
It's very important but it's also not remotely difficult.
More difficult to get down is the places where you do 6cc>236x>214A>dash 5c>2c>ender. also helpful to know.
Curious to hear any more you have to say about this. Certainly you'd have better insight into this than me. What're the hard/easy points of this match?
I'm just going to get this out there. You aren't losing because Bang is bad. I'm not losing because Tsubaki is bad. There may be some difference but it's mostly player skill. You just have to practice and get better. That's all there is to it.