iPhone XR stuck with apple logo after downloading iOS 15

I have an iPhone XR and tried to upgrade its iOS from 14 to 15. The download seemed to have finished, however in the next stage, when the phone is automatically restarting, the screen becomes stuck with a white Apple logo in a black background (without any loading bar under the logo).

I tried to manually restart by pressing the side buttons, but it didn't work. I tried then to restart it using the recovery mode by plugging it to a MacBook and doing the update once again. When the download finished it showed the following message: "Your iPhone has been updated, and is restarting. Please leave your iPhone connected. It will appear in sidebar after it restarts". However, right after this the phone shows once again the white Apple logo with the black background and it continues to be unresponsive. Interestingly, the Apple logo does disappear every ˜3min, but only for few seconds and then the logo is back in the screen again.

Could you please advise how can the issue be solved without having to erase all the files from my iPhone?

To note that the required space for the iOS 5 update was about 3GB and I had more than 8GB of free space on my phone.

Thanks!