I think you should make more clear, what people will get, if they give you money here.
The expected outcome would be to buy the early access version. But from what I could read about your plans, you will have to create a separate project to release the game here on Itch. Some people might not quite understand, that they did not buy the early access version that will get updates, but rather gave you support money only.
The term subscribing is ambigous. It could mean following. That is a subscription, since your followers will get notifications. What you wanted to tell is "to support the game's development without subscribing on Subscribestar/Elsewhere". In big bold letters that leave no room for thinking a purchase of this project will grant the full game later on.