Apple - Tap and drag delay

"without drag lock" is the correct setting for this – however, the drag lock only turns off after a half-second of inactivity, to make sure that the drag is finished. So, you must wait just a bit before touching the trackpad again.

You can also tap once at the end of your drag to release the drag lock.

If you use the "three finger drag" setting, no delay is required to move the cursor with a single finger.

You can try installing "BetterTouchTools" which removes the delay completely along with allowing you to add your own gestures.