My suggestion if you already have your AA status this year is to start crediting your oneworld flights to a
BA account now in preparation of your move.
This will build up your tier points and miles in the BA account, you can still use your AA status for any airport benefits on the flights you credit to BA.
Once in the UK look at the BA Amex, Amex gold card which currently offers 20,000 membership reward points for taking it out and the tesco MasterCard
All of those programs earn you BA miles, and if your flying WT+ will allow you to upgrade to CW where seats are available. The BA Amex will also give you a 2for1 voucher upon spending 10,000 (happy to refer if needed)
Also when in the UK you can sign up to tesco clubcard which is a supermarket loyalty scheme which allows you quarterly to move points to BA miles
cs