I've used a CooSpo one for about 2 years. It works fine nd connects over ANT+/BLE to everything, incl all the usual fitness apps and a PM4/5 monitor.
A couple of notes:
It has recently started not connecting immediately and I think it is the contacts with the battery. Newer models may have fixed this.
they say you can just disconnect the unit from the strap to switch it off, but I have found there is still residual current usage and the battery can run down. I just remove the battery now.
I also have an optical strap which is much easier to put on/take off. Note that with these, it is important to find the correct spot on your skin to mount it otherwise it becomes largely pointless. I have a large artery just under the skin on the inside of my forearm. If I mount the detector above that, I get readings that are very closely in line with the chest strap. So I tend to use that now.
I use the Scosche Rhythm+ which I like but it was super expensive at £70.
My sister couldn't justify spending that so got this one from Amazon instead and she has had no issues with it.
(I'm in the UK so link may not be useful but might be worth searching for same product there)
I've got this and does the job
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You can test it once you get it with the most popular heartrate app and it still work in conjunction.
However if you use this and use strava to track your speeds / distance and heart rate I wouldn't know how or if people do it that way?
If you want a fitness watch which uploads your activities to Strava get a Garmin Watch. The Watch will upload the data to Garmin Connect and IF linked to Strava will upload your activities along with your heart rate.