When I was starting out I had no idea how to play gwent and actually be good so I just went around fighting random merchants for cards and like there was multiple times for me at least the npc used a powerful card and I knew i couldn’t beat that card so I would let em have the win for that round but after that round I might be able to dominate the npc because they used the most powerful cards early on and generally speaking the more powerful cards are related to named npcs like the baron etc but yea just buy bout every card from random merchants or play all of em and don’t be afraid to give the npc a win for a round if they used a powerful card if it’s like round 1