Iphone 13 Pro Max Battery Drain

I recently bought Iphone 13 Pro Max (128gb). The battery seems to drain a lot. Is it because of IOS 15? I have turned off background refresh. In 30/40 minutes I lose 10 to 15%. I don't even do heavy use because of this drainage. Everywhere I see in YouTube, battery seems to be really great. Like in 1 hour only 4/5 % goes. Please help me with the solution. I would request Apple to give a software update for 13 Pro Max users to fix this battery problem.