It is old news, I shared it in the Iran topics.
https://www.sinodefenceforum.com/iranian-military-news-reports-data-etc.t7907/page-18#post-561478
So what ?
Iran 1.65 million square km, the S-300 batteries can cover less than 200 000 sqkm , the other radars maybe similar area , with terrain hugging flight path it is even less.
Iran has a lot of hills, means the problem of them was always the gaps in the radar coverage.
So, there is always an option to flight through Iran, and make nice pictures of the deserts. ( the SAMs are concentrated around population centres ) .
Add to that if they don't follow strict discipline with moving regularly the batteries and using mock up launchers/emitter and it is visible why they sacked the general.
But they managed to intercept the drone above the sea, so they improved a lot in the recent times.
However it is not about the capability of Iranians, but rather the capability of F-35 : D