Casio GBD H2000 vs Garmin instinct 3?

Hi,

I'm looking for a watch as an upgrade of my old protrek, features I need:

must have:

-accurate heart rate monitor

-vibration alarm(strong enough to wake me up)

-relatively accurate blood oxygen

-altemeter,compass,sunrise/sunset time

-phone finder: make phone play sound

-long battery life(at least 1 month per charge)

-fits OK on 15.8cm wrist

strongly preferred:

-flashlight

-smart alarm(wake when in light sleep phase) but must with accurate sleep tracking

-super long battery life(only turn on sensors when needed, can last months or years without charging)

After some research I found Casio GBD H2000 and Garmin instinct 3 solar. Did a little comparison based on info online (correct me if not true from your experience):

GBD H2000: better battery(says last 2 months without solar), have smart alarm, but bad heartrate accuracy(need confirm)? Also not sure how accurate and useful smart alarm is.

Instinct3 solar: better HR accuracy,have flashlight, generaly more functions, though not sure how long the battery will last irl (says 28 days without solar); also no smart alarm.

Any advice or experience sharing？ Thanks a lot!