Pretty sure S1 of AiB was out around a year earlier than SG, in 2020.

They both seem to go back a ways though - AiB is based on Manga that was serialised starting in 2010 - https://en.wikipedia.org/wiki/Alice_in_Borderland

And SG was apparently first written in 2009.

And yes, I agree it should get more attention! There are obvious similarities, but AiB appeals to me more in its mysteriousness.