Next, Sanity, Vercel and Typescript templates - Preview functionality

Thanks for a great tool, I'm enjoying exploring how it works. I'm stuck with one thing, though: the Next/Sanity/Vercel/Typescript starter appears to have the preview functionality set up, but it doesn't quite follow the different setup tutorials that I've seen elsewhere on the site and I can't get it working. The latest version is hitting a

ClientError: Unauthorized - Session not found

error. I've tried a handful of ways to handle this, including updating to version 2.30 (the starter uses 2.25, which looks like it's before some third party cookie issues were handled). Before going into lots of detail, is there a good place to find the setup for preview as it relates to that starter? (Specifically, I'm talking about this starter: https://github.com/sanity-io/sanity-template-nextjs-blog-comments/tree/e927176140cda50f89617cbff86c7689a726c3f1 )

For what it's worth, I tried this a few different ways and the latest attempt is giving me a

Not authenticated - preview not available

message. In Firefox, Safari, and Orion I don't get much more. Chrome gives the following trace. I saw an earlier similar message here, but without any responses...

Hello , could you try enabling cross-site tracking in your web browser (and then sign out and back into the Studio)? We think it might be related to cookieless auth and this would confirm it…When cookieless auth is used, next-sanity won’t be able to access previews because the auth token is stored in localStorage instead of a cookie.

Well, check it! It works locally and on Vercel! Is this a known issue that I missed in the docs, then, or a temporary workaround? I appreciate the help and am happy to do whatever to make it more clear for people in the future.