Space chess has 3 layers
4 player 3d chess

2 is definitely better for this variant to keep it more beginner friendly and not have to create new concepts for the layers as you could just use the bughouse setup.

Bug house is an apt comparison but here you can actually influence the other levels board , block pieces and maintain order as its still structured in that way.
Here is what I mean. I probably should have lead with that.
https://store.steampowered.com/app/3268290/ChessFinity/

That is really cool!!! Also, I meant bughouse as in that is just how they would show a multi-layered board; not that they couldn't influence other layers. Do you have any idea when it will come out because I couldn't find out anyhting other than "coming soon" on steam?

The demo is out and playable now - its pretty much the full product ( only premium feature will be custom deck creation in mana chess ) https://store.steampowered.com/app/3463010/ChessFinity_Demo/Yeah , it has an orthogonal ( top down view ) that shows both "boards" side by side that looks very similar to bughouse.
I think open beta will be around July.
My idea for this mode came about when I discovered raumschaht ( space chess ) - apparantly it is quite an old one ( Kazinsky had ideas about 3d variants ) but the game is played on a 8 x 8 x 2 board matrix. Where you have two sides stacked on top of each other ( depending on how you view it ) there are two teams , both teams have their partner above or below them. First side to get checkmated loses.
The pieces can all move between the boards , peons promote at the enemies end of the board ( it doesn't matter which level ) , they also can en-passent vertically as well as take vertically in addition to normal attack patterns.