Geopolitical threats arent evaluated based only on current and past conduct but must also take into account the capability of each actor, attempt to predict the shape of their interests as it morphs in response to the ever changing dynamics of the geopolitical stage.
In that sense, wether Iran did or did not support or host any baloch radical elements against Pakistan is only part of the equation, a more comprehensive view should evaluate what Iran is capable of as a whole and where do its interests and ultimate aspirations lie.
The radicalization of any sizeable Shia population outside its borders is an ability that the mullah regime of Iran have perfected and one that is detrimental to Pakistan's security.
Given Pakistans Shia population, merely radicalizing 10% of those would spell disaster for Pakistan, one can only take a look at Lebanon, Yemen or indeed, my very own Iraq to understand the extent of this potential threat, and the solution to this problem does not lie within Pakistan's borders but rather outside of it.
To control their Kurd problem, Turkey ventured outside its borders, attempting to change the geopolitical stage into one that while may not completely solves the problem, greatly minimizes the greatest potential damage which is the seperation of the Kurds, Pakistan should take note and realize that the only way to protect itself from a potential sectarian crysis is to make sure that the regional rival capable of taking advantage of this remains too occupied with other conflicts, itself needing Pakistan so as it wouldn't dare to cause problems.
As such, Pakistan should have a carefully calculated presence in the Middle east, create an enviroment where enough of Iran's wings are clipped that the gulf can see a benefit of having Pakistan, but Iran should still be kept threatening enough that they would seek its continued cooperation.
All for a price ofcourse.