If you like bullet hell shoot-'em-ups with 2.5D visuals, this could be up your alley.
Not much in the way of reviews yet, but there's a demo for you to try out before you buy. This has native Linux compatibility, which means it's highly likely to work on Steam Deck. It also has full gamepad support.
What might make this worthwhile is the shared co-op.
Also, if you like the soundtrack, you can buy it as DLC.
At C$19.49, that's probably the price I'd pay for it.