Did Brexit Trip Up Truss?

An article in the NYT suggests that Brexit is responsible for the speedy demise of the Truss government. Is that a reasonable conclusion?

I’m as fierce a critic of Brexit as anyone, but no. The Tin Lady’s Thatcherite persona and economic ideas long predated Brexit. Her lack of interest in expert opinion and the markets was largely inspired by BoJo, whose fall was due to shambolic administration and a failure to comply with rudimentary ethical standards. It is a mistake to over-analyze this; the fall of the Truss government was caused by its overwhelming unpopularity, its lack of credibility with the markets, and her always shaky support within the parliamentary party.

Now BoJo may be back. Brexit made him; it didn’t destroy him. Where does this theory go if he becomes PM again?