You are correct. This is due to how itch treats paid files on free or name-your-own-price projects, and when I raised the price later, it unintentionally removed access for earlier buyers. I am sorry about that.
To be clear, I absolutely do not expect you to purchase the game again and I am happy to send you the current build directly. This goes for anyone who is unable to access it after purchasing. Since itch doesn't have a private messaging system please reach out to me on Twitter/X, Bluesky or Patreon with a screenshot of your itch purchase & I'll send it to you right away.
Thanks again for supporting the game early on.