This might sound stupid but lately I have been researching Ottoman history and noticed out of the three famous padisahs(Selim the Grim, Mehmed the Conqueror, Suleiman the Magnificent) Suleiman's achievements seems like the most underwhelming one. Mehmed got Constantinople and unified the Anatolia with a mid-side empire while Selim defeated Mamluks and expanded the empire greatly in only 8 years. However Suleiman ruled a massive and very rich empire for 46 years and expanded the country not as much as the other two. Also, it is noticable that after Suleiman, Ottomans stopped expanding and started collapsing shortly after.
So the part that I don't understand is that Suleiman is glorified by a lot of people and considered as one of the greatest ruler of all time. Am I missing something? Thanks for any help.
P.S. sorry for any grammer mistakes that I made.
This thread won't answer your question, but do still think it's relevant in order to counter some of the points you appear to be making, such as success being measuered in how much you expand and leading onto that; the Ottoman decline theory. Here's the comment by u/Chamboz.
Here's a comment by the same user about Suleiman himself, a bit old at 4 years so a new comment would still be a good addition. :)