I was in the same situation recently and after comparing options, I ended up using the WHOOP 5.0/MG Activity Tracker (12-month membership). For everyday workouts, it’s been great. It tracks heart rate 24/7, gives detailed sleep and recovery insights, personalized coaching, menstrual cycle insights and the 14+ day battery life is a big plus. It’s comfortable enough to wear all day, not just during workouts.
The Polar H10 Heart Rate Sensor and Garmin HRM-600 are accurate but they are more performance focused chest straps. For general gym sessions, walking and overall health tracking, WHOOP feels more practical, and it works very well for heart rate too.