How can I make Lv.25 automatically?

I used to afk xp farm but It seems daily xp limit for custom game has set too low. I think it's about 16500xp.
Lv. 1~25 takes 337,500XP.
If I use afk xp farm, I need 21 days to make Lv.25.
Is there any faster way to make it Lv.25?

by playing the game ?