I don't think it'll be what you expect or what you left behind 6 years ago.
After 25 years in this industry (not all flying), I'm generally in a constant state of frustration by the attitudes, bull
and uninspiring "wonder-kids" I'm surrounded by! My experience counts for nothing, nor is it really respected.
I still enjoy flying and wish to continue, but my long-term plan is to leave the airlines. You have an opportunity to start again with a clean sheet, why not have a serious look at other options of professional flying, maybe on a part-time basis that you have control over, whilst enjoying the hedge-fund job?
My advice: avoid the airlines at all cost!