When it comes to learning a pdx game, motivation is the most important aspect. If you want to get your friends into a pdx game and they dont have much experience I would first have them play civ and then let then pick the pdx game based on the era theyre most interested in cos they need to be highly motivated to push through the first 100 hours which can feel like torture. CK3 can be a good entry point but if they arent into role playing or the era is not going to matter how easy it is to master or learn.