There's been a significant convergence of interests between Turkey and Iran on many issues. Particularly so when Israel and the GCC are making peace with each other.
Rather than herald the emergence of a new alliance in the region, the recent rapprochement between Iran and Turkey appears to be a marriage of convenience.
responsiblestatecraft.org
And in the case of Pakistan, Iran is an actual military threat to Pakistan, while the Saudis are not. And with this massive Chinese plan to invest $400B in a mere 5-year period in Iran, their economic and military muscle will expand far beyond Pakistan's ability to handle. Hence the need to make peace with Iran.
A weak state is nothing more than a shuttle cock.