UNC has almost always out-talented three-quarters (or more) of the teams on its schedule each year. Where we have frequently fallen short (and therefore has caused us to perennially underachieve) is that we either are at a serious disadvantage from a discipline and toughness standpoint (Mack 2.0), or from a game management and systemic philosophy standpoint (Fedora), or from a schematic standpoint (Butch Davis- offensively), or all of the above (Bunting).
Where I think Belichick will improve us primarily is in the discipline and toughness standpoint, as well as in game management. Improvements in those areas alone, paired with our usual penchant for fielding more talented rosters than 75% of our opponents in a given year, should enable us to win an additional game or two than we have been winning under the previously mentioned coaches. In other words, I don't think we're going to lose very many of our historic "WTF" games against an East Carolina, or a 1-5 UVA, or a 4-7 NCSU, or a Wake Forest, etc.
What I *don't* think is going to happen, is I don't think that we are going to improve our talent advantage and our depth enough to actually win games against teams that have significant talent and depth advantages over us. If we think we can pay players now, there's always going to be a Clemson, Ohio State, Alabama, Georgia, Texas, Tennessee, Ole Miss, Florida, etc. that's going to be willing to pay more. We'll win some recruiting/portal battles, to be sure, but I can't see us winning enough of them to be able to win a conference championship or compete legitimately in the CFP (though, to be sure, the expanded playoff will at least give us a fighting chance to at least get there in the occasional year where everything breaks right for us). I'd love to be proven wrong, but I think we'll see this play out against Clemson this year, Notre Dame/Clemson next year, etc.
With the preemptive caveat that, again, I absolutely, positively would like to be proven incorrect, I stand by my belief that 72 year old Bill Belichick and his NFL staff aren't going to be here long enough to build an actual college program that has the talent and depth to win championships of any kind. But I do agree with other posters who hope that, regardless of how thing whole Belichick experiment goes, it will at least raise the floor for the UNC program in terms of commitment of resources moving forward.
Edited to add: Looking ahead at our future schedules, IF- and it's a massive *if*, one that I think will be a 'no'- but IF Belichick is here in 2027, that's a schedule that UNC can use to make a CFP. We play one team that should have a talent/depth advantage against us, and that's FSU, and it's in Chapel Hill.