External heart rate monitor won’t stay connected

I have had so many issues with my iwatch staying connected to my Bluetooth monitors. I have tried multiple it used to work just fine and now it takes forever disconnecting repairing turning on and off Bluetooth repairing for it to work! This should not be an issue and it’s making me more and more looking into a different type of smartwatch! For how much we pay for one of these watches we should be able to use the features that are suppose to be functional.