Can I make one input make it so that another input I'm holding is double tapped?

As you can probably tell from the drinkiness of the question, I'm looking to do something very specific, that I highly doubt Google would be able to find.

So I'm trying out a game called Cosmic Break Universal, which only has gamepad mode and mouth/keyboard mode, which means it is impossible to use the mouth and controller at the same time (and I tried it with just a controller, it is horrendous). So I'm using steam input to emulate a keyboard on my controller, so I can use controller a mouse controls.

The problem is that this game only lets you assign a dash button if you are on gamepad mode. On keyboard/mouse mode, there is no option to set a dash button, and you can only dash by double tapping one of the directions. You can see how this would be problematic on an analog stick. Normally I would just set the dash button to click it in the left stick, but the game does not let me do that.

So I kind of have my current setup be moving with the d-pad, and set the left stick to a radio menu, which could work, but is a little unintuitive. So my solution: set it up so that when I click in the left stick, it doubles whatever input I'm holding for WASD, such that it acts as a dash button. Problem: I don't even know where to begin to do that.

Does anyone know if this is possible? If so: how may I go about doing this? Thank you in advance!