SO, on some specific models of steam deck, specifically the OLED ones, From Madness With Love is bugged and that causes the game to be almost impossibly inconvenient to play.
You see, steam deck OLED's come with HDR screens, which crank up the brightness on a game. From Madness With Love, however, responds to this poorly (for some reason, I don't know enough about tech to tell you why).
This causes the game to be insanely, insanely bright. Like, actively "makes your eyes hurt" bright. I've never seen anyone mention this, and after pulling my hair out trying to find a solution, I finally found 2 possible ones.
Option A: Set a launch option
go into the launch option settings (properties -> general -> scroll down), and copy and paste this string into it:
DXVK_HDR=0 %command%
Option B: Switch to proton 7.0-6
Properties -> compatibility -> check the box -> scroll down -> click "proton 7.0-6"
I know this seems simple in retrospect, but considering how obscure this game is, it was extremely hard trying to find a solution anywhere. I hope this helps anyone!!