That's very unlikely, it's too new, maybe in 1-2 years if at all. Games that end up in GOG Connect are older games that the devs don't expect make much money from anymore. If you want it on GOG you're better of just buying it now or when on sale.

I wouldn't count on that, at least for some time. This game was released on both platforms at the same time, so you had the option to choose which one you prefered.
Many Connect games are games that were released much earlier on Steam than on GOG and, as a deference to buyers that didn't have the option to get a DRM-Free build before, devs make that game redeemable on GOG Connect.
Some others are oldies that are usually part of cheap bundles and giveaways.
But neither is the case of Cultist Simulator...

I bought it on gog. Want it on steam as well so I can attempt the steam link app on my phone with it lol.