The advantage of choosing a game that is well known as an Esport is that the infrastructure and resources are already available to support playing games professionally. Long-standing Esports titles such as League of Legends, Dota 2, and CounterStrike: Global Offensive (CS: GO) have a large and specialized player base, plus sponsored tournaments that offer big prizes. The downside is that the game is a difficult arena for newcomers to enter.
When a game is and will be popular, players have the opportunity to help dive into the dame and advance the meta, which tends to be more volatile and accommodate different styles of play initially. Early gamers from games like Rocket League2 and PlayerUnknown's Battlegrounds3, for example, were the way to propel them onto the Esports scene. However, there is also the risk of competitive gaming arenas failing to survive, which is when you may have to choose a new game.
Apart from individual talent, the culture surrounding gaming also influences playing games professionally. Before investing too much time in learning the details of a particular game, spend some time monitoring forums and other gathering places for players. The experience will provide a better clue of the path forward, and you will be able to judge whether the pro player's journey fits your personal goals and motivations.