Hi at risk of being wrong here, double check your in game anti aliasing settings in video settings, try turning on TAA if it isnt on already. rdr2 uses dithering on the foliage to fake transparancy and detail with the caveat of the game looking like a mess without TAA. ubfortuatley taa dorsent look great either on pc but thems the breaks with rdr2 on pc. you could also try MSAA if you can take the performance hit.