M4 Aqua stuck on blue waves because blinking LED

LED blinking makes your device won't run, device will overheat and battery drain.
Just you need to stop blinking LED goes to blank by holding power + volume down about 5-10 seconds and sony reboots normally.

My own phone in April 2020 stuck on bootloop, but unfortunately, it's irrecoverable phone and plenty much dead. Charging will not work, the motherboard was unscrewed and fried over there.