掲示板 Forums - なくて vs なく

I understand the difference between なくて and ないで, but what about when the て is dropped and only ～なく remains? I think i'm understanding a bit, but I'm still slightly unclear

Also, I found out this form when searching for a way to say "there was definitely a live feel"/"the live feeling definitely reached me!", and came up with 間違いなくライブ感で

Perhaps there's a better way of saying this?

があった does seem like it makes more sense, and thank you for the explanation!