(Again...took forever to correct typing errors...eyes. So hope this helps as I am giving up on more edits)
ATRAC is active by default.
To turn it off, poke (don’t hold down) the traction button (car with wavy lines under it).
Holding same button down for 3 seconds while stopped turns off VSC too.
To turn off only VSC, press center diff lock button. This dumps VSC and keeps ATRAC.
ATRAC uses automatic application of brakes to stop wheel-spin.
VSC tries to compensate for loss of traction in turns in dirt, etc.
I turn off VSC on slippery dirt roads by hitting center diff lock.
If having trouble keeping momentum up and over steep obstacle, turning off ATRAC can sometimes help as it stops applying brakes.
No single answer best.
Depends on many factors.