Hi Anton,
As I mentioned in this thread, the multisession preview can still work if you use our fork of gatsby-source-prismic-graphql that we are still maintaining.
As mentioned in the blog post shared before we don’t recommend this plugin for new projects.
If you need a plugin that is a future proof solution that is recommended by Prismic, then I would advise you to use the gatsby-source-prismic
Note that the multisession previews feature don’t work currently with this plugin.
Furthermore, if you need to use more stable SSR that works with multisession previews then I would advise you to use Next.js
Please let us know if you need any further assistance.