Best alternative would maybe to use a third party controller that has a turbo mode. If you're on Switch, I'd recommend the Binboks (I don't know why the main seller has so many listing for their same controller). Or the Kyldans if you don't need rumble. I personally like the clicker feeling of these buttons. I've personally never used turbo modes; but it might be worth considering.
Also, I wished they finally let us (even as an option in the menu) to switch R1 and R2 to fire.
I've found one app for android, but it's old, japanese and only for ge2rb... But i guess GE3 and GE2RB similar so if you know Japanese you can use that
I couldn't find the one I got in my PS4 on Amazon anymore, but perhaps this one can also solve your storage problem for the rest of this console generation like it has for me.