Hi.
Made an almost identical move at the same age as you from London based orange to BA. Don’t regret the move personally, although some have.
Positives: Slightly better salary, much better pension and fringe benefits, more opportunities, more responsibility.
Negatives: Rubbish being junior, big company culture, inefficient operating systems (rostering, phone numbers that don’t work, list is endless)
Initially your lifestyle will be the same or even worse, but things gradually improve depending on when during the recruitment cycle you join.
Send me a PM for anything else.