Is the Substar version charge more money than itch?
If it's the same price, and the dev forced in this arbitrary 2 weeks delay, then they are very shitty for doing that.
(Still shitty for charging more money for Early access, but everyone is doing it at this point.
Only passable excuse is if there's technical difficulty that they can't. But again, it won't be a certain "2 weeks delay", as they would try to solve it as soon as possible.
Unfortunately there are rarely regulations to make these devs behave.
Tho that makes pirating more appealing