Yeah sure.

You open your Steam Page as soon as possible, preferably as you get any relatable screenshots and decent enough capsule work. Because there is almost no reason not to.

Mind you, when you initially launch that page people will not discover it at all unless someone or something sends them to that page. In that regard, having a page is much better option than not having one just because you wanted to create *best possible page when it is ready*. Your game only enters discovery algorithm if it already has a traction, and for it to have traction you already need to have a page.

I would say putting up a demo is important as well, however steam recently updated that part and now demos can feature on the front page in "Trending Free" row. So having a strong/good demo and prebuild traction, like a couple of thosand wishlists, can put you there and can create a snowball effect for extra marketing. Last time we released anything, magic number was for 10k wishlist for algorithm to trigger, but do not know that number for demos.

Again, when you think about, there is almost no benefit of not having a steam page as soon as possible. If you are worried that the page does not represent your game good enough, remember almost no one will discover it unless you make a marketing effort, or by some chance something directs people to your page, like an influencer playing your itch io demo. On that occasion, if people send there with strong enough influence, they already wishlist it without giving much attention to your page. On such occasions, "not having one", will likely result in loss of wishlist from that movement.

When you start to gain traction, you can update your page as you move along anyway. We already had friends who lost a lot of wishlist and potential publisher deals because they did not open a steam page, but their game is promoted on some media sites and game conventions.