Doing the Scavo Firebolt challenge After 10 losses in a row :)

This is me attempting a Challenge from splinterlands for the first time,

now the way I normally do battles is I have to try and put 2 melee tanks in the first two slots, the more hp and attack the better, I do try and ensure that the second of the two has reached to ensure all of them are attacking in a turn at any one time

then depending on the tileset I try and put 2 magic in the middle with boosting effects wherever possible, and then add in two ranged in the back and safe with snipe if possible, but it does depend on mana but failing that I would put a 0 mana in the last row for sneak protection

This battle was done in a Ranked Gold 2 league

Now this battle worked well but the last 10 didn't so what did I do wrong

If you have any advice please tell me, as I'm always eager to learn and get better at this amazing game