WI: Ottomans march to Buda before fall of Belgrade

Belgrade was main fortress protecting southern border of Kingdom Hungary. It was able to withstand major Ottoman attacks in 1440 (especially that siege is worth to mention-Belgrade's defenders survived, despite being left completly on their own, as Hungary was in anarchy after death of Albert Habsburg) and in 1456.

Suleiman, who dreamed about ridding on horseback through the streets of Buda from the very begining of his reign, initially planned to march straight to Hungarian capital, leaving unconquered Belgrade behind his back, but sanjakbey of Smederovo convinced him, that it is bad idea. What if Suleiman don't listen to his advise and decides to march deep into Hungary, ignoring Belgrade? Fortress of Belgrade was not in particulary good shape in 1520s due to lack of funds, but was still of big value, being protected by two big rivers, and its crew was composed of elite Hungarian troops.

So what if instead of attacking Belgrade in 1521 Suleiman goes straight towards Buda? Leaving Hungarian fortress behind was maybe not the best idea, but due to internal troubles of Hungary-lack of funds, bad shape of the army, could he still be successful and get high reward for big risk? Or maybe failure of his campaign is more likely outcome? Both scenarios would bring interesting consequences-if Suleiman achieves earlier Mohacs, then Habsburgs, who fights against France, would be distracted by Ottoman threat, OTOH if Suleiman failed... That depends of scale of his defeat-Hungary may buy some time (that means Habsburgs could concentrate more on Italy in late 1520s) and Persia could take advantage of Ottoman troubles.
If Louis II still attacks the Ottomans on field, Hungary still loses. Whether Louis II survives or not is up to our assumptions. Could be, maybe not. The Ottomans will demand yearly tribute, Belgrade, Zemun and Petrovaradin from Hungary.

If Louis II waits out in Buda, Hungary has an advantage. The Ottomans cannot storm a city with a garrison 20-30k troops without massive casualties. Louis II can wait out until relief forces, be it Zapolya or from Austria.
Militarily, the Ottomans are still stronger. A defeat in Buda would not result in the same defeats as in 1684-1697. The possible death of Suleiman causes political unrest. But by then, he has no other son left than Mustafa and Mehmed being either born recently or about to be born. Mustafa is Sultan aged 7, his mother is his regent and if Ibrahim survived the defeat, odds are likely that he gets influential as OTL maybe even more. Mehmed will likely be spared to make sure the dynasty lasts. Hurrem is banished to a different palace.
The Safavids attacked the Ottomans when Suleiman was in Vienna, so a defeat or victory does not really matter. They can probably start raiding Ottoman Frontiers again. But it would have to wait for Tahmasp I to become Shah. Ismail was an alcoholic after his defear in Chaldiran.