Listen people take sitting seriously, if you ever are at a company fire sale keep an eye out for these: https://www.amazon.com/Herman-Miller-Embody-Chair-Graphite/dp/B01DGM7ZKQ
I'll update you with a build in a few but the ryzen build above is pretty standard though I would make some changes. How many mouse buttons do you like to use in wow? And do you want a headset with a built in mic?
I'm in the US, but you're right about the pricing, I looked at the Amazon listing and didn't dig any deeper, my bad. https://www.amazon.com/dp/B01DGM7ZKQ/ref=cm_sw_r_cp_apa_fabc_UzGcGbGJC5KRA
Embody friend this guy:
https://www.amazon.com/Herman-Miller-Embody-Chair-CN122AWAAG1G1BB3513/dp/B01DGM7ZKQ
Will be returning it, obviously. Really frustrated I paid $200 more for the higher end upholstery and got the lower end one. Pre-sale prices below.
ASIN I bought ($1,695)
https://www.amazon.com/dp/B01DGM7ZKQ
ASIN I got ($1,495)
https://www.amazon.com/dp/B07NH4D496
Black Balance ($200 more)
https://www.hermanmiller.com/en_lac/resources/materials/textiles/balance/black/3513/
Green Apple Rhythm ($200 less)
https://www.hermanmiller.com/en_lac/resources/materials/textiles/rhythm/green-apple/3002/