Update 1.1:
1)I have added an option to apply the extra yields to Capital city only (default ON, if you switch it OFF in Advanced Options you will have the mod working for all the cities).
2) Removed Gathering Storm dependency, mod loads different sql files based on your expansions and dlc
3) Added compatibility with most popular resource mods:
3.1) Resourceful Lite - https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2842798579
3.2) Resourceful (original version) - https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=889162746
3.3) Resourceful 2 (maintained version) - https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1369684991
3.4) Sukritact's Resources - https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1150492115

The mod changes the yields of the city center district. Flat tiles get 3 food 1 production guaranteed, Hills tiles get 2 food 2 production guaranteed. Rest is compatible with civ6 formula