Where is that dang third gym

I am having trouble locating the third gym, i have maxed out my team's level to the level cap of 40 because i havent beaten the third gym but i can't seem to find it.

The misty npc says it should be in a savannah, but i have searched the entire savannah biome that have came across with no luck, also i have no idea what to do with the map i got at the start which tells me where the first gym is, how do i make it locate the next gym?

An i just dumb or am is the spawn rates bad on my seed?

also i have found several duplicates of the first and second gym and have found the fourth gym which i have put a waystone at to teleport there for after i find the third.