You want to build your posterior chain, not just your lower back. Deadlifts and squats are great, but you also want exercises that do not affect your CNS to that extent but give you benefit. Reverse Hypers, Hypers, Glute Ham Raises, Pullthroughs, Band Good Mornings, these are all good. Good Mornings are good as well, but you are going to need to watch volume as you rotate all this stuff around.