Go for the older rigid Garmin Strap, the soft straps can fail after a bit as the salt in sweat contaminates the band and you get erratic readings.
Rinsing the strap every so often helps, but my premium one only lasted a year, before getting problematic. It would take a while to give a reading and then over time started to spike, then wouldn’t go above 130 and then stopped reading entirely.
Replacement rigid one has been faultless so far. Link to Garmin, there are cheaper prices elsewhere, Amazon was the best deal when I got mine.
https://buy.garmin.com/en-GB/GB/p/10996