In theory, the victory for Boris Johnson means he can't face another no-confidence motion for a year, securing his position in Downing Street. His position is different.
Weakened prime ministers are vulnerable to plotting, and their authority can be further undermined by rebellions among lawmakers in Parliament that make it impossible to get key legislation through.
Resignations by ministers, particularly senior ones, can cause serious damage to leaders, especially if they are orchestrated. Johnson's cabinet is heavily made up of his supporters, making this less likely, but it is not impossible. There were rumors this year that Rishi Sunak, the chancellor of the Exchequer, might quit, and if Mr. Johnson tried to demote him in a reshuffle, such speculation could return.
The rule that there can be no repeat of a no-confidence motion for a year could be changed by the senior hierarchy of the Conservative Party in Parliament.