The game uses DX 11.1 which is notorious for poor performance with certain gpu's, namely AMD.
God of War also uses DX 11.1 - on the steam forums people were pretty curious why PB coded it for DX11.1 and not DX11.3 or DX12 when the minimum OS requirement is Windows 10.
I wouldn't hold my breath that PB makes it work with Windows 7, because on the official page for the game from several sources, 10 is the lowest OS supported.
Don't kill the messenger, sorry I don't have good news. You might be able to finagle it to work on your Win 7 machines but it won't be officially supported in any capacity, to the best of my knowledge. Which is dumb, because it uses a branch of DX11.
EDIT: Here is the store page on GOG, where you can see Windows 10 is the required OS: https://www.gog.com/en/game/elex_ii