If it doesn’t work out for you, try the Smartshaker .
I tried a number of gadgets (haptic smart watches, phone alarms) before I found the Smartshaker. I set it to highest vibration, no sound. Slip in my pillowcase under the pillow. Works every time. Also, it’s stupid easy to set or reset the wake time(s), and it can go several months without needing recharging. Highly recommended.