Best Fitness Tracker, Expert Recommendation to Choose

[mony313]

I am looking for the best Fitness tracker as my doctor advised me to start monitoring my daily activity because my energy levels have been dropping lately. i have been experiencing inconsistent sleep and trouble keeping track of my steps, workouts, and heart rate. i went through reviews from trusted sources like CNET, Wirecutter, and Android Authority and after comparing many options these two kept coming up as the top choices:

WHOOP 5.0/MG Activity Tracker - 12 Month Membership - Health and Fitness Wearable – 24/7 Activity and Sleep Tracker, Personalized Coaching, Menstrual Cycle Insights – 14+ Days Battery Life

https://amzn.to/4j3aV9u
Garmin vívoactive® 6, Health and Fitness GPS Smartwatch, AMOLED Display, Up to 11 Days of Battery, Slate with Black Band

https://amzn.to/44Yll48

however, i am having trouble deciding which one would be better for me and i would love to get your expert advice and hoping maybe some fitness trainers, health-tracking enthusiasts, or anyone experienced with different wearables on this forum can also share their advice.
i usually go for morning walks and light workouts, but i also want something that helps me stay consistent and keeps me motivated. would either of these be recommended for me? Any suggestions or advice would be appreciated.

Thanks in advance