Battle challenge 5 to 7 should be ready,you can check it out. And congratulations 🎉👏 for achieving 1 to 4.
There is a lot you can do with your sparks,there is the new one just announced by the community,the arena vanguard foundation cards, though 30k sparks per one,there are outfits and hats you can buy with them and as well as various skins. Anyway, wishing you more wins as you battle on.