if you're going through security at an off-peak time, clear via TBIT regardless of whether you have tsa pre. they'll let you through.

if it's busier AND you have tsa pre, clear via T4 (again, they'll let you through) and walk to TBIT via the new connector.

to connect to your UA flight, you should make a few considerations. first, the tsa pre lanes close at about 10pm in T6-8. it's much quicker to walk from TBIT to T7/8 airside and outside (15-20min walk from the lounge to T7 security) than it is by walking airside through the tunnels (30-40min walk). yes, it really takes that long - and it's easy to get lost.

you could try to catch the AA T4-T6 shuttle bus at gate 44 to shave off 10min, but (a) there may be a wait, and/or (b) they might not let you aboard with your UA BP.