Windows 10 has some repair systems you can try but no OS so the usual is malware or other OS damage then hardware issues like a failing HDD.

The killer issue is safe mode fails. Part of what you write does sound like what I see with HDD failures.

As everyone understands backups are not optional you can try the factory reset. If the hardware is good, it will work again.

-> There is another way in on some machines. Use the backup spare admin account. Worth a try but unlikely due to the safe mode failure.