Threshold detection

Hi - I've got an HRM dual and an HRM Pro (my second) where the rubber is deteriorating. On my first HRM Pro, the same thing happened. Eventually I suspect that both straps will become unwearable.

The manual for my Fenix 7 says that for threshold detection, it needs to be connected to an external Garmin HRM. Is this correct? Would a third party HRM provide the same information? Alternatively, does the wrist based OHR do it?

I normally run with a strap but given how my Garmin HRM's are deteriorating, I'm considering branching out to another brand but want to retain the same functionality.

Thanks very much.