Huawei y3 hangs in boat loop?

When I recently started YouTube on my Huawei y3 360-u61, the app crashed suddenly. After that, all system processes crashed and since then, the boot loop is stuck. After a factory reset and a successful flashing with the SP FLASH Tool the right firmware has not changed. It still hangs in the boot loop and sometimes displays the lock screen, but disappears after a few seconds as the system processes support. So just like before the factory reset and flashing the firmware. What else can I do to save the device?

Try if you come in the fastboot that you do by pressing the volume up and down + on and off if the device has a menu button down in the middle, it may be that you still have to press but first only both volume buttons and the on and off button

And about the fastboot you should look for the app that caused the problem and uninstall them