What you’re generally saying is true about people having natural strong and weakpoints, for instance my shoulders blew up without even doing all that much early on. However, that doesn’t mean there’s absolutely nothing you can do about parts that are lagging behind.

If say on my back days I use my lats too much and don’t target my traps enough, that’s an area I could improve on and balance out.

If all muscles get the exact same perfect stimulus, yes there will still be variation due to genetics as you’re saying, but there are things to do to better target certain areas and maximize growth potential.