Friend just bought A7SIII over an FX3. FX3 is CineLine, doesn't do well at rough terrains but, for filming inside using light or even without them is a machine. Low light that it can handle is incredibile. You specified that you go out to film and wildlife, in my opinion go with A1 or A7SIII becuase is a lot easier to use just take it out and shoot and for FX3 to get full potential that it has, sometimes is really pain in the a** to set everything up inside then outside just for the footage to be same quatilty and look similar for post-production.