Dota 2 results
The idea that eSports games do not require very powerful hardware seems to be true. A casual PC gamer would be satisfied even with the Radeon RX 550 in all cases. Pro-gamers demand at least the maximum refresh rate of their monitor and if they play shooters they usually demand even more than that. If you can spot your enemy earlier even by a millisecond, you'll get a competitive advantage.
Dota 2 is the only game of our selection that is not a shooter. On medium settings the game already looks quite good, however the game clearly prefers Nvidia cards. The GTX 1050 easily achieves more than double the frame rate of the RX 550 and the GTX 1060 3 GB beats out the RX 580 by far. In any case, you won't need an extremely powerful card for this game.