if anyone discover how I would also like to know, i tried to do 2 runs choosing only pro-mert/ayrtom respectively and still didn't get their cg's maybe I'm missing something?
when you play through from the beginning you gotta do 3 things
hint below
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1. choose only Mert or Artyom choices
2. fail to help Wei relationship (on cooking contest part, choose any other choice except "Lu rou fan")
3. fail to help Heleen relationship (on island part, when Heleen ask for advice choose other choice except "Tell her to follow her heart")
then you help the rest of other characters (Berno and the brothers, old lady, Rene) , choose no to Mert/Artyom proposal 2 times, follow the rest of story and you should get first 2 CGs (either you choose Mert or Artyom only route).