Blackjack do also has a lower house edge than the rest of the games while I don't know if how much is the house edge on poker but if you are a skillful poker player, you have a good chance of beating the house. These two games are still best if played in offline especially poker because there are methods in poker which only works IRL. Hunting high multiplier and hunting for the jackpot are seem close enough.
I don't play card-related games because I don't understand how they work. But I remember I tried to learn how to play card-related games with my friends, and I ended up learning a little. But that was a long ago, and I don't remember what I've learned. Whenever our friend circle meets on any occasion, they don't miss the chance to play card games. Unfortunately, I cannot join them because I don't know how to play. So, I end up scrolling social media while they play.
I feel like it is exactly similar to learning anything else. You learn the cards, you learn what is better than the other thing, you learn the odds, you learn basically whatever people teach you, like for poker, there are poker courses and it teaches all you need to know, there are beginner level classes at first, but then you can do advance as well if you want to.
After that, it is just all about using what you learned and gaining experience, just because you studied doesn't mean you will just purely make profit, even the professionals loses sometimes, but they do overall win that is why they are professionals. So after learning and after gaining experience, you will be able to beat most amateurs, and as long as you play online, there will be plenty of amateurs to play against and you will be able to make a profit.