Garmin's Venu4 product likely hasn't undergone rigorous testing. I've used Garmin products for over nine years and experienced two instances where my outdoor running watch crashed and wouldn't turn on. Both happened with my Garmin Venu4.
This time, the watch crashed and wouldn't turn on, even though the outdoor temperature was above 12°C. The system version is the latest, 15.16. I already sent a debug file package after the previous crash, but haven't received a response.