itch.io

i mean you can literally pay it right after you press download, and you can even choose the amount you want to support

Publishing a game on steam requires the author to pay 100.00, and since this is a free game, there really isn't any revenue to make up for the lost 100 besides donations.

Though this is only one of the reasons the author might not be able to publish to steam. Also, it is why indie devs publish to itch and not steam.