Average/below average teams can squeeze into the playoffs and get a win, you see it every couple of years usually teams from the NFC South or most recently AFC East, when teams get a one off playoff run.
The Bucs this season are a pretty good example of a mediocre team squeezing into the playoffs and beating a team didn't have any right too.
The Giants in 2022 overachieved with a very weak roster and we're lucky enough to play against the worst defense in the NFL in the wildcard.
Unfortunately that roster was exposed this past season, with many glaring holes QB being the biggest one since without that your nothing in the NFL.