You're setting the right-side anchor to the right point on the nameplate, then applying an offset. When you scale up, naturally, the texture will start overlapping the nameplate again. What you need to do is set the left anchor of the texture instead to the right point on the nameplate.
I would also hook
NamePlateDriverFrame at the point when it creates the unitframes. Less chance of affecting other parts of the UI.
Lua Code:
hooksecurefunc(NamePlateDriverFrame,"AcquireUnitFrame",function(base)
if base:IsForbidden() then return; end-- Prevent modding forbidden frames (accessing these throws errors)
local unitframe=base.UnitFrame;-- Set by original function
unitframe.ClassificationFrame:ClearAllPoints();
unitframe.ClassificationFrame:SetPoint("LEFT",unitframe.healthBar,"RIGHT");
end);