Save iPhone (Endless Reboot, Endless Loop Apple Logo)?

Last night I tried to create storage space on my iPhone 8 Plus, but I tried to delete the 10GB Netflix app (with downloaded films), which my iPhone stopped responding to. Without thinking too much I wanted to restart my iPhone and since then it has been in this endless loop of starting (the Apple logo lights up and disappears again and so on).

A reboot (briefly louder, briefly quieter, press and hold the power button) is for the iPhone to be switched off, but if I then switch it on again, it will not be fully restarted. After that I tried to "update" the iPhone in the maintenance state via iTunes but after a few minutes an error message (14) occurs and iTunes advises me to "restore" the iPhone.

However, I want to avoid this loss of data. Are there any tips? Many, many thanks in advance

Had the same thing too

You can't avoid restoring

if necessary, just call Apple but they will only tell you that

Aren't you doing regular backups?

Is it somehow still possible to save the data? Didn't do the iCloud backup regularly

No, unfortunately not, but I only did something regularly and actually had everything