Bug of IPhone 11

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

If the issue persists, something could have gone wrong during the latest update procedure.

I would try to install a fresh copy of iOS. To do this, create a full backup of your iPhone (1), then restore it to factory settings (you need a computer to perform this step) and, in the end, set it up as new (2).

When done, restore data from your previously made backup (3).

Follow the instructions provided in these support articles:

(1) How to back up your iPhone, iPad, and iPod touch – Apple Support

(2) Restore your iPhone, iPad, or iPod to factory settings – Apple Support

(3) Restore your iPhone, iPad, or iPod touch from a backup

If the issue still persists, contact Apple Support directly using this link:--> Get Support

Regards

Giulio

You can start trying a "forced restart" of that iPhone, using these instructions:--> Force restart iPhone – Apple Support

Many times it solves that kind of problem.

If the issue persists, then yes, you need a computer running iTunes to perform the "restore to factory settings" procedure I described.

Regards

Giulio