If you are an EXP and/or flying J or F on AA, T5 is a cake walk. I went through there yesterday flying 81 home to DFW. Walk in the main terminal, go all the way to the right (zone J) and walk into the F area for BA. Look to the right and there are two AA staffed and marketed check in for customers who are emerald/EXP/J/F. Security is right there what is a huge bonus and takes all but a few minutes and you are plopped right into their F lounge. The lounge is average and unlike DFW's "flagship" lounge there is nothing out on offer (except drinks, pretzels, and mixed nuts). You have to order everything to your seat. I think it's a carry over from the covid excuse days but since I wasn't in this lounge prior to covid I can't confirm.
You exit down an escalator and then a long one down to the train to take you to B and C gates.