iPhone XR stuck in Guided Access and keeps returning to YouTube

Re: My iPhone XR is locked in guided access and keeps going back to YouTube. I tried hard restarting but it keeps going back to YouTube.

Guided Access is set up that way, in order to confine use of the iPhone to one app.

Wondering if you set it up yourself, and whether or not you set up a method of exiting Guided Access.

Use Guided Access with iPhone, iPad, and iPod touch - Apple Support

Eg: says:

"Set up Guided Access

1. Go to Settings > Accessibility, then turn on Guided Access.
2. Tap Passcode Settings, then tap Set Guided Access Passcode.
3. Enter a passcode, then re-enter it. From here, you can also turn on Face ID or Touch ID as a way to end a Guided Access session."

and

"End a Guided Access session

Triple-click the Side or Home button, enter your Guided Access passcode, then tap End.

Or

if you turned on Touch ID or Face ID for Guided Access, double-click the Side or Home button."