A lot of the roster is the same and we saw Mac Jones have a very solid season especially for a rookie.
So what's the biggest change that's likely affected things? Oh that's right, letting McDaniels go and basically replacing him with those BOZOS Patricia + Judge. Those guys definitely aren't capable of helping a QB develop and sadly we're seeing it now.
Mac certainly has his flaws/limitations, but I'm sorry I don't know how someone who looked good last season suddenly looks bad and also lost/lacking confidence in a span of a season. And unlike previous years where you see McDaniels on the sideline coaching up Brady, Hoyer, Brissett, Garoppolo, etc. I don't see any of that now, it's just Mac and the offense mostly sitting amongst themselves.
Btw, notice how good the Giants look with Judge no longer there? And I know the Lions are still bad but you can tell they love their coach and they still had some exciting stretches here or there. The Lions currently have Goff at QB too while Patricia had Stafford. If they still had Stafford now there's no doubt in my mind they'd be solid too, but Goff is just not a good QB either.