My boss and a long time good friend developed one[1] with his previous indie studio. Originally VR but playable with mouse and keyboard too, player can shrink both themselves and their enemies.
(Not trying to advertise for sales as the company went under years ago)
All those major studios listed have their own game engines, so unitys decisions don't affect them anyways. And Epic develops Unreal Engine, so Unitys' loss is their win.