I do a lot of cycling and hiking... ...so pretty much exclusively cardio. I don't feel like it's holding me back, but I've been vaping for several years, so it's hard to say if it is and that's just normal for me. I was going heavy when I was smoking and that was really holding me back. I improved drastically over that first month before proceeding gradually to a comfortable plateau.
There is of course a point where ramping-up the effort just cuts into stamina with no real benefit, but that point is far beyond where I want to be. It might be that I'm plateauing because I don't want to go further. I'm at a point where I just maintain. If I start declining, then I'll have to change some things.
If I wanted to go past that point, I might try vaping significantly less and see if anything changes. Only one way to find out, yanno?
It's generally good practice to do a bunch of little things that may improve your performance if that's your goal - as long as the change isn't potentially harmful, then it's a good change to make. Sometimes it really IS just a combination of little things that make the difference. I call it lifestyle micro-management. Of course it takes more than few tweaks to hit goals, but it can't hurt to cut back on anything that doesn't benefit you. I think it's safe to say that vaping isn't doing you any good. Whether or not it's holding you back is harder to say, but still...
Honestly though, I think I'd be assessing my diet and workout routines/habits first. Maybe there's something you need to attack at a different angle. What makes you think it is vaping? Did you smoke before you vaped? Has vaping had a direct impact on your performance before? Or is this a more recent observation?
I will say that I DO feel it if I vape immediately before a ride. Sort of an immediate wall with my breathing and vigor. It passes after a few minutes. I don't experience this when I wait a half-hour after vaping to hop on my bike. When I'm hiking I tend not to vape at all because it is literally almost 100F outside and I don't need any help losing water lol. 2-3 puffs here and there doesn't seem to cause me any problems, though.