I don't consider ZZ in the Southern Rock genre. Their early stuff was blues with some Tex-Mex influence. Their later "Eliminator" stuff was pure melodic rock with some blues ballads.
Texas is part of the south no matter how much Yankees whove moved there swear otherwise
Ive argued that here forever.
Like the origin of the Lone Star flag and so forth
Ill grant ZZ Top is different in a way Skynyrd and Molly Hatchet are similar
Liberals adore Drive By Truckers as Southern rock ..well because its a very lib and I mean Uber liberal band....but its not southern rock to me although the south is all they sing about
Blackberry Smoke is a Georgia band identified with Texas but is very southern rock sounding...
Its kind of complicated.