I just read this in a youtube comment( I know, I know) and it seems pretty solid, So I added some more points to make it concrete. Jon Snow nor Dany are Azor Ahai reborn.

Rhaegar Targaryen was, he was born under a bleeding star, amidst salt and smoke, with the blood of the dragon. Another thing is When you read about Rhaegar it says he was born during the Tragedy at Summerhall where fire was used to wake the dragons.

Lyana is Nissa Nissa (Azor Ahai's wife who was killed when Lightbringer was made), which means that Jon is Lightbringer. Also Rhaegar never claims he isn't the prince. He simply says "I will require a sword and armor. It seems I must be a warrior," and people let it go. But that's not a no.

Points against it being Jon and Dany is that it requires a prince(ss). Dany is a Queen, which is a step up, and while Jon is neither, he is closest to King of the North. Alas poor Rheager lived and died a Prince.

Lastly is the Song of Fire and Ice, that comes with the PrinceGRRM himself said "I mean... Fire is love, fire is passion, fire is sexual ardor and all of these things. Ice is betrayal, ice is revenge..." Who fits this more than Rheagar? He and LS fell in love, and their union ended with a child. However R was married at the time, and L was promised to Rob, a betrayal of their houses.

TL;DR Jon Snow is a Sword.

There's definitely holes in this, but it blew my mind so I thought I'd spread it around.

*Made a mistake with the star. Technically his son was conceived under the star, which (based on their consummation laws) means his marriage had just been 'birthed.'