My iPhone 11 Pro Max is stuck on Snapchat

my iphone 11 pro max is stuck on Snapchat but i can still go to my lock screen and reach siri but she wont move me to another app, its on good battery i've been trying to turn it off by holding the side button and volume button but if i hold for too long it starts beeping, please help i dont want to go to the apple store to get it repaired and we just bought it on christmas its basically brand new

[Re-Titled by Moderator]