It is currently possible to connect Huawei devices only to Huawei approved services.
The Huawei Health app can only transfer data to certain services approved by Huawei. These include for example Strada, Adidas Running or Komoot, and therefore Huawei devices can only be connected to HeiaHeia via these apps, as long as they can be connected to Google Fit or the Apple health app. Unfortunately, there is a higher chance of errors, but you can try to connect using the following path: Huawei -> e.g. Strada -> Google fit or Apple Health -> HeiaHeia.