As someone who actually did it I'll give you my take. Yes I am one of those few E3s that came back and got a job in Australia. That was my choice..Great job, great flying but living in the USA long term was not for me..I did not enjoy that part. Other's loved, it each to their own. Going through the process of getting a job back here after my USA experience was generally positive. Certainly was never looked at as "cheating" etc. Nor did I ever receive any "Dey Turk er jerbs" type of treatment from anyone in the US.
I will however offer this advice, have an out or an end game. Majors may never happen nor may the E3 be sustainable long term. Yes you may get lucky with the lottery or you might settle down with a local (my wife may not have approved of this option). But as some said, you've got some FO or PIC time at a part 121, what now? Whens the next down turn etc.
I think everyone in Aus will hire plenty this year (subject to COVID, WW3, market crash etc) and anyone that wants to come home will be in with a massive shot.