i don't mind occasional newsletters for big sales/my wishlist game sales/free games/important newsfrom GoG, but i really loathe the pointless "exclusive" discounts valid for my account with a discount code (that are a pretty unsympathetic marketing tactic imo, shame on you gog)

is there away i opt out only from those? or i have to create a spam filter in my email client?

Use these settings. I only ever get wishlist discounts.

Create a filter, that's what I did. Exclusives spam is under "promotions and hot deals", and if you unsubscribe from that, you'll miss out on sales emails, too.

Proof of purchase emails are sent by do-not-reply at gog.com.
2 factor auth emails, no-reply at email.gog.com.
Wishlist emails, do_not_reply at gog.com. (underscores)
Sales, high-profile releases, and exclusives spam, newsletter at email2.gog.com. I set up my mailbox to send emails from this group which contain the word "exclusive" straight into the trash.

oh well, if anyone else is interested, here's a spam rule i've creted for outlook