Boot loop

You need a computer and this is the standard fix...

Frozen phone or Logo Bootloop

see the process below. Work all through it.

If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

There is no guarantee you can save any data since your last backup

Try it several times after which you will need to take it in for repair - but that probably means a replacement phone

https://support.apple.com/iphone/repair/service