I think there's a danger of over-responding to the most recent datapoint:
1) Our run game isn't necessarily out of the woods - Buffalo is awful against the run, period. I am very encouraged by using Drake's legs more in the red zone which is absolutely a schematic / tactical change that should have durable benefits. I do think ironically our backup O-Lineman seem better at run blocking than our starters (particularly Jared Wilson), but again that has come against a couple of really bad run defenses (Giants, Bills). The most encouraging thing has been Henderson seemingly improving his vision a bit and if that continues it will absolutely be a big boost to the run game / offense overall.
2) The passing offense is still the strength of this team. In fact I think because we were so explosive in the running game (and our defense kept giving up long drives), we essentially put ourselves in the position that our Brady-era Patriots often put other teams in - our passing game was completely out of rhythm due to not getting many opportunities. The Bills also have a very good pass defense, but that's not going to change in the postseason as we will likely have to play 1-3 games against the Bills, Texans, and Broncos so we better buckle up.
As for run defense troubles, that's more than a single datapoint - we are bad defending the run right now. Whether that's injuries, wear and tear of the season on a team with poor depth even for defenders that are still out there, or something schematic, I can't say. Williams and Spillane being back will certainly help but I'm not sure that's the only answer. Against Buffalo a lot of the issue was simply missed tackles. James Cook is an elite running back but good lord, I don't know how many times we fought the blocking to a relative standstill (0-3 yard gain) and Cook managed to turn plays into 7-10+ yard runs. Regardless, we have to get it fixed to a degree where we can be at least league average.
On special teams - this hasn't generally been an issue for us but I'm surprised on Sunday they didn't start instructing Borregalis to just kick the ball into the endzone and give the 35 rather than continually giving up 50+ yards. 35 isn't great but it's manage-able. Giving Josh Allen a start in Patriots territory is not manage-able.