I was talking with some buddies about this topic earlier today. Just a little anecdote on how high-variance turnovers can be:
Last season, Xavier McKinney finished with 8 INT. As a team, we had 23 INT.
This season, our whole team combined for 7 INT.
Last season, S Kevin Byard had 1 INT, and CB Nashon Wright had 1 INT in the last 4 seasons combined.
On the whole, the Bears had 11 INT.
This season, Byard led the league with 7 INT and Wright had 5 INT. The Bears as a team had 23 INT this season.
Right now their defense is EXTREMELY turnover-dependent, too. In both EPA and DVOA they are bad-to-mediocre defensively. They are also amongst the worst teams in the league in pressure rate, and consistently were gashed in the run game. If those turnover numbers regress at all, I'd expect that defense to struggle.
And on top of that they have limited room to work defensively. Last year the majority of resources were dedicated to the offense and supporting Caleb (which is fine) but they don't have a ton of flexibility on defense now. And with regards to turnovers - Byard is a FA. Brisker is a FA. (They have no safeties under contract next year currently IIRC) Wright is a FA. Jaylon Johnson has been great in the past but lately has been hurt a ton and hasn't played well much of this season.
Don't get me wrong. As a fan of the game, neutrally, they're a fun team to watch. And of course I'm not 100% objective. But I think Chicago fans may find that the idea of a "open window" is often more theoretical than reality-based and will be disappointed when they don't observe linear progress onwards and upwards next season.