What do you mean by “4x4 post bracket”?typical post bases handle lateral displacement - prevent the bottom of the post from getting kicked out - not hold posts upright. There is special hardware that you can bury in concrete to do that - it’s called a moment post base. The ones I’m familiar with, the concrete gets poured around it; it isn’t something you can bolt to a footing afterwards. And they’re at least $150/each for a 4x4 version, just for the hardware. Can’t remember height limit off the top of my head, but fence heights are often limited by code, and model code max I believe is 7ft. https://www.strongtie.com/standoffpostbases_castinplacepostbases/mpb_base/p/mpbz#ProductDetails