mirkokovac Error: Failed to execute 'claimInterface' on 'USBDevice': Unable to claim interface
That error means you have something else running on your PC which is interfering with webUSB. Close all other programs and tabs in your browser, return your phone to the bootloader interface, reconnect the USB-C cable and try flashing release again
If it still doesn't work then, restart your PC, and try flashing again.
If still not, restart your phone into the bootloader interface again, and try flashing again.