Hi, Sorry for the late reply.
You don't need to activate premium plugins such as SliderPro, Slider Revolution, WPBakery plugin, etc in CityTours theme.
You can use them without activating.
And I can see you added slider in tour pages already. https://www.radugatour-marmaris.ru/ekskursii/arenda-vip-yath/
Please tell me what other issues you have with CityTours theme.