PVG flight uses Gate 133 in TBIT for arrival (as do HND and SYD flights). Domestic flights use T2/T3. You'll need to clear to Customs/Immigration/TSA just as you do with any international flight to the US connecting to an onward flight (except from cities with pre-clearance). You can either clear TSA in TBIT and then take the airside shuttle to T2/T3, or clear TSA directly at T2/T3. Others can chime in on which is faster as I don't have personal experience. The walk from TBIT to T3 is pretty short. The 9PM LAX-LAS flight generally departs from T3 (you can check the flight history on flightaware.com).
https://www.delta.com/content/www/en...s-angeles.html
Didn't realize they tried to always use their 1 TBIT gate for this flight. Last time I flew it (3 months at or so) we went to T2.
OP,
While it does look like the PVG flight usually use TBIT, if there's a delay with previous aircraft it can goto T2 (where majority of DL international flights arrive).
If TBIT there's a bag recheck belt just before the exit. Can drop bags here and make way to T3. (Note while LAS flights are normally T3, they can end up out of T2) Quickest way to T3 is to walk there. If you clear security at TBIT, you'll need to catch a shuttle to T3.