Ok they do spawn in the 30 gg cave in fact all do it’s just luck , bit like getting a red or blue Godzilla in there you get both dragon and boss
As for the maze they spawn both sides or routes if you prefer , the thing is that on mob respawn it selects x z y dragons to spawn there is no guarantee a fiery drake will spawn on that turn ,
It’s pure luck being in the right part of maze etc ,
As the days go by less and less players will need in your level bracket so hang in there ….