tactix Charlie

If you want to accurately track HR, get a watch that can sync with a chest strap HR monitor. I have the Garmin Tactics Charlie and the chest strapnHR Pro which is waterproof so you can swim with it. It's probably too bulky for you, but check battery life. I charge my watch once every 3-3 weeks.

I wear a tactix Charlie, about 2019 vintage, daily. It gets loads of abuse, gets strapped on the outside of my drysuit and used in water rescue, it does about 1-2 hours of GPS activity a day and battery lasts about 4-5 days doing that. Without GPS use I get about 8 days battery life.

100% worth it. I've had my Tactix Charlie for 5 years now, and the display still looks brand new. The bezel is pretty beat up, but the sapphire looks flawless

I3 tactical for field work/deployment, Tactix for leave.

I spent good money on the tactix. It's great. I've beaten and abused it. It's a tank. Does all the smartphone nonsense and way way more. Lasts about 20~ days on a charge so I can actually get all the telemetry back when I sleep and it's useful.