Possible to downgrade ios 26 to 18 without a computer as I don't like it

My iPhone 16 Pro Max was upgraded to iOS 26 one week ago, and honestly, I can't stand it. The battery life is terrible, the phone feels laggy, and I'm just not happy with the changes. I really want to go back to iOS 18 before I completely lose my mind. I've been looking around online and I see a lot of conflicting information. I understand that downgrading isn't as simple as just hitting a undo button. What is the safest way to downgrade iOS 26 to 18 with or without a computer? I saw a few guides about using iTunes, but I've also seen suggestions for third-party tools . I'm not super tech-savvy, so I'm looking for the method with the lowest chance of "bricking" my phone.