If you fly YVR-TPE-BKK-TPE-YVR your $800 will go to about $125.
If you fly YVR-SFO-TPE-BKK-TPE-SFO-YVR you will pay a few dollars more (I would expect about $200 total) but get to experience Eva's industry leading "Royal Laurel" business class product which is so incredibly much better than the older version they fly on YVR-TPE-YVR. (Individual pods, Dom Perignom, Rimowa amenity kits, etc)
But to answer your question, yes you will have lounge access
Are you based out of YVR and starting/stopping there? If east coast, replace YVR-SFO-TPE-SFO-YVR with YYZ-TPE-YYZ and you skip connecting in the US and still get the new royal laurel service.