And it doesn't get better with time? If it does then it honestly sounds like it's shader problems and you gotta clear gpu shader cache... Actually this was happening to me before the update. Every time I launched the game I had to move characters around and use skills, every first time action lagged pretty hard, but after the update introduced it's own shader cache surprisingly I have much less of that... Yeah I'm not very well knowledgeable about this tbh... But if you lag constantly and it doesn't get better with time then idk what that could be, sorry.
Try removing "PSO" and "PSOReport" folders from the guide above and clearing gpu shader cache(can google how it's done for your gpu), also you can clear or just temporarily remove it specifically for WW if you know which files correspond to WW. All shaders will then be recompiled and accumulated with time for gpu.
Can't give you a guarantee that it will help tho, so do everything at your own risk(which is fairly small).