(original commenter) I submitted the Request Trial form from a Google Workspace admin account, and a couple hours later got another email to download a Duet Handbook (20 page PDF), which required submitting contact info again. The bottom of the handbook just had "Contact sales for access"... with a link to a sales contact form.
Edit: our org also submitted the google form multiple months ago requesting beta access. My (un)educated guess is a lot of what's in this blog post isn't production ready and they're handpicking accounts to onboard for specific features.
I would be pretty amazed if they launched everything in that blog post in the near future.
Is Google's product org just a total dumpster fire? How can you put out a blog post saying a previously invite-only product is GA, but then have the product still be invite only?