For me it's pretty simple - I have a blacklist of OP cards/synergies.
If anyone plays Renfri, two scenarios in one match, Yennefer's Invocation, Highland Warlord, Magic Compass, Golden Nekker, Witches' Sabbath or Arachas Queen, I send my most disparaging taunt two or three times, forfeit, no GG.
The only way to stop people using these stupid broken things is to refuse to play them.
I understand this sentiment — even to the point of holding a similar attitude myself at times.
But for such an approach to work, there would need to be a uniform agreement amongst players of exactly what “deserves” this treatment, and the agreement to immediately forfeit (denying the joy of playing). And here’s the problem — I don’t think players would come close to agreeing on a list (for instance, none of your cards would have even grazed my list — I tend to object more to binary than OP).
Honestly, there is now so much brokenly powerful stuff that one almost has to play some of it in a viable deck. For example, with the last drop, I have abandoned my hatred of Cahir because it is the strongest counter to most of the new OP garbage I hate even more.
Ultimately, it needs to be up to the developers to reign in abusive cards and keep the game fun. And I must say that I think the latest patch has significantly broadened the set of potentially viable decks (they are binary as heck, but that is a different issue).
So I try to GG except in cases of egregious poor sportsmanship (which can still be very subjective). And I must admit, I often fail to uphold this standard when I get tilted by what an opponent plays.