It should be the Shift-key by default. If you’re pressing the Left Mouse Button to move and encounter monsters, you can press the Shift-key to start attacking, without lifting the LMB. It essentially acts like the Function key (FN) you find on some keyboards. It changes the LMB function from Move to Attack.
If I understand you correctly, I don’t think this is causing the problem. I’ve always played this way. Even though I’m not using the term accurately, I call it “chording”.
I play a Demon Hunter too. My most played builds are Unhallowed Multishot, Marauder’s Multishot Sentry, and GoD. In that order.
I press and hold the LMB to move. When I encounter monsters I press the Shift-key without lifting the LMB to start attacking. When I’ve secured the area, I release the Shift-key to continue moving to the next mob.
While doing this, I also spam 2 keys for Vengeance and Companion, without releasing the other keys, when they’re off Cooldown. I occasionally press the key for my Hatred-spender. Also, without releasing the other keys.
With GoD, I start by getting my Momentum stacks up. Then, I start Strafing. Every few seconds I release the Strafe key while still holding the LMB. Then, I press and release the Shift-key to fire off a Hungering Arrow and continue Strafing.
The Hatred-spenders and how often I use them depend on the build.
- For Unhallowed it would be Multishot / Arsenal.
- For Marauder’s it would be Multishot / Full Broadside.
- For GoD it would be Strafe / Rocket Storm.
I’ve never had issues killing monsters. My previous highest Greater Rift was 112. So far, this Season 30, I’ve reached GR123 and still climbing.