I think beta should be burninated as it’s a meta tag. Beta hardware, beta software, which software all beg the question.
I strongly prefer beta seed program for questions about that service. In reality, macOS or iOS should be the tag and the beta status and version should be in the body, not the tags. Just like you need to be specific about what version of macOS you have when asking a normal question, doing that should be the gold standard and people don’t need any beta tag to know, but I understand the easy use of meta tags and popularity of them.
The down side is a meta tag might make it easier to ignore or follow pre-release software. I wonder if there’s consensus to make the tag beta-seed-program to be appropriate for developer seeds, public seeds other seeds and have it host questions about how to get in, how to apply and things that may narrowly only affect a beta build?