So I wanted to post the usual deck that I use when the cost of a battle is around the 25 mana mark.
I usually have a level 2 one of this summoner but I recently rented a level 3 one to try to see if I should buy/upgrade.
The torrent fiend can be swapped out for a similar 1 cost if you don't have and when you have more mana try to keep the style the same but upgrade the unit. an example would be changing the cruel sethropod to a better tank minion.
usually when I have more mana allocation I look to change/increase the Mana cost of my 1st position unit first then I add a better unit onto the 3rd position usually with high health/armor.
and lastly, id changes the ranger to be one with a higher attack or the snipe ability as this will be useful for mage encounters.
I hope this helps you endeavor out of the bronze rank.😁