Hello, like I said in this video (somewhere around 2:00 plus at the end of it - let me know if you would like to see my reaction to (rewatching for the second time) aespa's MVs for : Black Mamba, Next level, Savage & Girls (for more info - please watch the whole reaction)
Good first reaction, personally I'd prefer each SMCU episode followed by corresponding MV, so as to keep it fresh and more relevant. FYI en.wikipedia.org/wiki/SM_Culture_Universe has a quick recap of all main characters and terms.
Probably don't need to react to something you already watched before. You can just catch up with everything you missed and get ready to react to their comeback coming soon. Don't have to be an expert in their lore unless you really want to and can still enjoy without too much thinking.
Thanks for reacting to the lore vid! You could check out the SM Culture Universe EP2 as well, and then go back to Black Mamba, Next Level & Savage. I could understand those MVs (and lyrics) far better after seeing the lore. Eventually, you can check out EP3, plus Girls again. Be prepared for some more goosebumps and incredible action!