Garmin
Forerunner 255 Series
Long battery; but wrist HR tracking is inconsistent.

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Fenix 8 47mm Sapphire. I've had a range of Garmins (Forerunner range: 35, 235, 935, 945, 955) but the 970 didn't appeal to me (accent colour on side and domed glass) so I got my first Fenix and first AMOLED watch (solar was thicker than my 955 which was already a bit thick under clothing). Love the look of the Fenix a lot more, plus better battery life
I would look for a used or refurbished Garmin Forerunner 35 or 45 (whatever you can find for cheapest). Also just to note, GPS is what allows watches to accurately measure distance and pace, so you’ll want a watch either GPS. However for the ultimate cheapest option, if money is really limited, consider just using a running app on your phone instead.
You're welcome! And yeah I agree, using a phone is super cumbersome. Having a watch is so much more convenient! Even though they can be pricey, I think they're a good investment. And the longevity of Garmin Forerunner watches is quite good in my experience. And also they stay fairly valuable as long as they still work, so if you eventually decide to upgrade to different model, you can still sell your old one!
Forerunner 35. Still usually holds it's charge for an hour or so. I might be shopping soon.
I use an old cheapo Forerunner 35 which is ancient. I just broadcast heart rate to my bike computer when I don’t wanna wear the strap. Does the job.
Garmin Venu 1, 2, or even one of the newer Vivoactives would be great. You can get a Venu 2 for probably about $100-$130 on Facebook Marketplace right now. You can also get one of the older Garmin Forerunners for about the same price as well, if not a little cheaper
Use forerunner for swimming and it works great. So happy I no longer have to count my laps and I can just swim.
Garmin
Forerunner 255 Series
Long battery; but wrist HR tracking is inconsistent.

Garmin
Forerunner 955 Series
Best value, clear MIP screen; limited smartwatch features.

Garmin
Fenix 7 Series
Durable, multi-week battery, flashlight; high price, buggy software.
Garmin
Instinct 2 Series
Rugged, solar multi-week battery; bulky, small screen readability issues.

Garmin
Enduro 3
Multi-week solar battery, lightweight; but bulky form factor.

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Oura - Oura Ring Series

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Apple - Ultra Series

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Garmin - Enduro 3

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Garmin - Fenix 7 Series

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Garmin - Forerunner 255 Series

Ranked #1
Oura - Oura Ring Series