There are SkyTeam lounges at both PVG and TPE. As a GM/SkyTeam Elite+ you are eligible to use those lounges on international itineraries; you don't need to be a SkyClub member.
https://www.delta.com/skyclub/viewSk...Request.action
You can also use the SEA Delta club if you are on an international itinerary. If you want to use the SkyClubs on your domestic trips you will have to join or buy day passes.