Pretty much all of Iran's "own fighters" have been vaporware so far. This is pretty well known. They cannot really make anything of their own with all the crippling sanctions that isn't overly cheap knockoff.
That said, it doesn't mean that they can't test new stuff. Most planes start off as drones and eventually move to production. Most of the Russian and various Western jets that jumped up in generation had severe teething problems of their own (F-22 and F-35 make great examples here), and those nations actually have great expertise in designing these planes, not to mention economies that can support huge development costs associated with these programs. Iran lacks all of these.
Iran could, and likely is working on something. It's highly unlikely to be practical and working fighter jet, just like all of its previous fighter jets. Beyond the propaganda bullshit, it shows that with all the sanctions, they still have some degree of expertise and skill and every once in a while they have to show off something like this. Something that will never become a practical application, but to show that they still have some semblance of capability of making a high tech device.
And then they sell their anti ship missiles that cost next to nothing and manage to cripple a high tech Israeli ship. Or have a NATO general win war games using nothing but their low quality, but cheap and numerous hardware against significantly more technologically advanced NATO forces.