Probably will get one from Hot Toys right away. I think InArt if they ever do it, will be a bit later down the line as they already have the BVS version coming first along with quite a few others.
I'm hoping that InArt could offer both at once (bit like we got 2 Jokers and Batman & Bruce Wayne sets, even though those were variations from the same film) but realistically I expect both InArt and Hot Toys to hold off until he's got a solo film or a bigger role in Black Adam sequel. I don't think anyone (even Hasbro) have done figures just off a post-credits scene before.
At around $500 a piece I can only get one so I'll have to pass on BvS and cross my fingers we get one like this later since (for me) this is the best he's looked so far.