Lexico gives a definition of "in itself":
Viewed in its essential qualities...
So this means that the essential properties of the framework (of seeking the thing you are passionate about) is a trap. Presumably he means that you will become trapped in the search, and not enjoy what you already have. It is a stoical point of view.
Lexico gives the example (slightly simplified here):
Bringing up a family is a full-time job in itself’
The phrase "in itself" adds very little to the meaning of the sentence. It suggests that "bringing up a family" is a full-time job, and it can't be made less than a full-time job.