Lol, Extremely simplistic & innocent thought which is extremely far from reality.
Nobody is leader in muslim world. A leader is one who everyone follows and everyone accept it as a leader.
Like every country, Iran look after only its own interests. It funds Houthis and Hezbullah only for its own geopolitical gains. Iran helped ruined & completely destroy Syria by giving a new lifeline to a dictator Bashar al Asad who was very close to be thrown out in arab spring. Syria would have survived that long suffering. Syrians will never forget what Iran did with them for its own geopolitical gains. Iran would use any muslim country as a tissue paper for its purpose. Its nothing against Iran but that's how the world is. KSA & Turkey have their own geopolitical objectives. Iran simply can never imagine to be their "leader' as these countries have opposite objectives, a sea of differences, none of these or any other country would ever follow such a controversial "leader".
Iran fought a great war, but don't mistake it as anything done for "muslim world" or even Gaza. Iran didn't fired a single missile when day in and day out IDF was dropping 2000 lbs bombs over residential complexes, hospitals, refugee camps and turning entire gaza into rubble. When Israel had completely turned Gaza into piece of rubble it turned its attention towards Iran and planned to eliminate a future threat (Iran's nuclear program). Only when Iran itself was attacked only then Iran retaliated. Iran won't care if any other muslim country is attacked. If Turkey, Azerbaijan, KSA, Pakistan, Egpyt, Libya, Sudan, Indonesia, any muslim country is attacked Iran would literally say who gives a f-k. So please remember they only fought for their own country. They didn't fought for "muslims" or Gazans or anyone else.