How often is the data updated?
The data is updated every hour, both for the leaderboard and the statistics of all ranked and normal modes
Why do all the gods have so few games?
The data is cleared after each big patch in which the gods are rebalanced and the maps are changed, this is done in order to see the actual statistics of the god in a new meta
Why are the statistics in 1x1 or 3x3 look suspicious sometimes? Gods with 100% win rate in 1x1 with 100+ games, are they OP?
No, this is due to the frequent abuse in these game modes. But in most cases it is easy to notice.