If it is Samsung BLE issue then it would be Samsung but since it worked previously that doesn’t sound likely. You need to use the Samsung Members app to submit reports.
Finally this is not the right place Samsung’s mobile developers do not follow this board to prevent any potential dispute or misunderstanding as to the similarity between Unsolicited Submissions and our internally and independently developed products, technology and services.
Re Samsung - I don’t have a Samsung phone but I do have a few Samsung Watches. Is there any other option?
Re Google - The “How to Submit a bug in Android Wear” article seems outdated to me. It might relate to Tizen watches which had this app and could connect to iOS as the article suggests. These days there is no Android Wear and no iOS support AFAIK.
Re this board - Do Samsung’s mobile developers follow the Mobile board?
Samsung’s mobile developers do not follow this board to prevent any potential dispute or misunderstanding as to the similarity between Unsolicited Submissions and our internally and independently developed products, technology and services.
If you are sure this is only on the GW5 update to OneUI 5 I think you can report this to the Developer Support team but it may take a while to get this to engineering.