Imagine having a strong AD with Awacs backed bvr capable jets denying airspace over Iraq, Syria, Jordan.
You can raise F35 to some unbeatable untouchable marvelesque / avengers status, but it will also need to take on evasive measures if it detects a couple of bvrs coming its way. Iran's prowess with HGVs and ballistics means they can develop capable SAM/AAM, just need a suitable delivery platform. Plus its not like the sky is full of F35s only. There are other prized assets you can take out. You can achieve local air superiority theaters (Swift Retort, 2019), and use older 3rd gen planes to achieve strategic objectives.
Invest in every possible defensive/offensive weapon, and maintain a healthy balance. Should pakistan stop investing in its AF now that we're a nuclear state?