Whenever I get to the “Log In” point on the author certificate it just doesn’t show anything
I assume you are using Galaxy Watch Studio. It used an old java library that used Internet Explorer to open the Seller Portal. Microsoft discontinued support for IE last year and the store blocked connections from IE because of the security risk. Bottom Line is you cannot use Galaxy Watch Studio for tizen to generate certificates.
If the error just says your Distributor Certificate has expired then change the year on your computer and Watch and it may allow you to Run on Device.
If you are a new developer You can jump through some hoops and run on Device using TIzen Studio and an old gear app installer tools.
Samsung Developer Relations