After the purchase, you will continue to receive versions in accordance with the purchased "privileges". Roughly speaking, when you buy a game, you do not buy a specific version, but versions of the game in accordance with the release schedules of the game and versions for different levels of "privileges". Itch works like something from which you will receive privileges with a one-time purchase and then, as if you bought a game in steam, but at the same time, yes, it is better to support the game on patreon monthly, if you liked it so much, then you get more privileges.