It might sound like a cliche, but I recommend the old but gold one, CSGO. Many of us played it at least once, which is proof the game is good. It captivates you a lot, and I cannot say it is hard for beginners. You will also see your growth without problems, and the main benefit of popular games is that you can quickly get some help online if you don't understand something; there are many players out there willing to help a novice. There are also many platforms for skins exchange, such as Skinsmonkey, which make your game a bit more interesting.