You need nothing.

Just get out there and start driving. Buy a 4WD guide book that lists all the essential driving techniques and provides trail ratings and enjoy the learning.

A stock TRD 4R is very capable and a Pro is also fast.

You will learn NOTHING if you start with a modified vehicle especially one where a fancy suspension is coupled with spacers. Stronger skid plates and sliders are fine, of course, though not needed until you drive difficult rated trails (for 4x4 vehicles, not buggies).

A stock Pro will drive 99% of the available dirt roads and 4x4 trails that actually offer something other than a mile or two of crazy rocks. If you want to fool around in OHV parks, get a UTV. Or do a SAS to an old 4R. The only new vehicle that is both a vehicle and a toy in one is the JL Rubicon.

I had spacers for years. On a Subaru. There were no other options. And no premium suspension from the factory either.

EDIT: especially for California! Get the Charlie Wells California book, has all you need to get going. There is no need to drive the Rubicon, Ersy Dusham, or Fordyce to enjoy going offroad. There is so much in UT/AZ/NV/CA before, if ever, one feels the need to go to the hardest trails.