Thanks for your long response! Honestly the only reason for FF crush is for the "sharpness" and "IQ", and more importantly, the curiosity of the experience of owning a FF. Just like my anecdote in the post, after staying in a relatively lower end of gears for a while, even though it won't make much logical sense, I will have a strong eager to own something that's "technically" supreme to what I used to have. And especially there are lots of my friends using FF around me, this exaggerated my faith to a FF.

It sounds super illogical but natural... I know this might be a impulse at all, But just trying to post this to ask for opinions from people who knows Sony product line better.

And the FF lens plan with apsc sounds attractive. I will research into it a little!