I noticed two new options that allow you to use your Apple Watch as a HRM for a BTLE enabled cycling computer (Developed as a Peloton solution but seems to work with cycling computers).
They both work pretty similar (one is software and the other is hardware) by running an app on the watch that transfers the HR to the phone which then transfers the HR to the computer.
I tried the software version as it's free with ads. I used it on a Lezyne Super GPS and once it was running seems to work very good. The issue I have is with setup. It seems as though you have to go through the pairing process every time you use it. I'm not sure if this is a shortfall of the Lezyne or just the way it has to connect. I then tried it on a Garmin Edge 530 and couldn't get it to sync once it was paired. Maybe it's just buggy as a new release. I think I'm going to order the hardware version and see if it's any good. Has anyone else tried these?
Here is the software solutions.
https://apps.apple.com/us/app/blueheart-bluetooth-heartrate/id1485503543
Here is the hardware solution.
https://npe-inc.com/news-highlights-home-page/heartbeatz-connects-apple-watch/