Holding down the reload button for 2 to 3 seconds while your weapon is empty will automatically use a synth, from your inventory, for said weapon type. If synth is still on cooldown you would see a timer next to the ammo counter. This would allow us to use ammo synths while in combat and avoid being killed while in our inventories activating said synths. Would you like to see this be implemented into the game? Let me know what you think. Could just hold down trigger to activate synth or trigger + reload to activate. The point is we need a way to activate synths without going into our inventories during combat. I wouldn't mind having synths mapped to d-pad either but seeing as how those buttons were used for emotes I don't know if Bungie would be willing to deactivate emotes in combat and give us a hot key auto synth feature for the d-pad. I just chose to use reload button as an example since it's familiar. Bungie could code it so when opening a chest, planetary material, sparrow, pike, or ghost it doesn't activate auto synth as well.