What Iran needs, is to swallow the bitter pill and recognise that its air force is dead. And when the challenge is staring down and water is already up the neck, there is no time to resurrect. They need at least 5 years to be able to secure their skies on their own. Only acquisition of jets wont do, they need to modernise their bases to house such 4.5 gen aircraft and ensuring their safety on ground, they need new radars, air defences, AWACS, air refuelers for sustain CAPs during hostilities (Iran is a huge land mass). Plus training for personal on all these force multipliers. Time is of the essence, and Iran is already out of time.
While Iran rebuild its airforce, there is no option for them but to come to some sort of alliance with Pakistan and China (have to ditch India completely) in safe guarding Iranian aerial frontiers. That obviously means PAF/PLAAF aerial assets flying across Iranian airspace at the time when its needed, as deterrence. In return, Iran could offer free energy guarantee for next couple of decades to Pakistan and water tight assurity that India will be ditched once and for all.