I don't know how you would define "better", but if you mean higher quality, I'm certain that most people would be able to pick out the DSLR version in a "blind" test, even if you used the same approx. lens focal length on the DSLR and the phone (e.g. 52mm when comparing to iPhone). I would guess people would prefer the DSLR one, but it's simply a guess (and I'm biased because I know more or less what to look for).
I'm not sure if I'd say that most people would be able to tell. But I'm sure photography people would be able to tell. Unless you're a wannabe influencer or a working professional, what matters is not whether other people would be able to tell. Nobody cares about your pictures. What matters is if you can tell, and how it makes you feel.
I think if you let them zoom in to the edges they'd pick it easily enough. My iPhone always blurs a few little details, little part of a hat sticking out, thinking it's the background.
