I use the Garmin asl well. Super easy to use. Connects right away.
Garmin 010-12883-00 HRM-Dual Heart Rate Monitor https://www.amazon.com/dp/B07N3C5WRG/ref=cm_sw_r_cp_api_glt_fabc_BFJWN24XB2VNK93WHWVK?_encoding=UTF8&psc=1
I've been using the Garmin HRM-Dual for over a year now. I've had to change the battery a couple times. There have been one or two runs where the reading was clearly wrong, but I restarted the run, reconnected the HR monitor, and things were back to normal. Otherwise, it's been a good heart rate monitor.
It doesn't work in the water, but it doesn't seemed hurt by the water. I wore it during a triathlon this summer, and as soon as I came out of the water it started working.