I can see this happening tbh. Not anytime soon bc BTS is still a thing and will comeback soon but after BTS, NJ has the most potential. Tbh i was really surprised with NJ's concept and music, i haven't heard/saw everything but from what i have they are different. Their sound is something i haven't heard before in kpop. Cool with you and ditto and very unique to kpop. It's not just r&b, it's chill and has this laidback vibe. Even super shy, which is cute-ish still has that vibey laidback sound woven in. I usually hate cute songs but this was actually good. Their music video for ditto and cool with you was so unique as well, a welcome change. Though i didn't like the super shy video at all...
All in all, if they keep this style up i can see them being the most acclaimed alongside BTS one day. Maybe they could surpass them when BTS decides to call it quits or rarely promote together.... But that's far far off.
For them to really surpass BTS they would need to bring just as much money, and even BP with all their success couldn't to do that, but time will tell.