I think if there was a practice mode where you can use any consumables and any guardians without using the ones you already have, it would be helpful. People could also make the opponent have specific buffs and things. This is just an idea but I think this would be a pretty cool feature.
I guess that cant be done due to the nature of the mode thats aims to be roguelike, these kind of games rely on replaying the game with different scenarios and combinations of power ups but here in KI you can save these power ups to use them when the scenario requires it, for example like Fractured Guard guardian helps a lot against Gargos or Ram against Omen crazy kick combos.
Maybe a replayable tutorial mode?
The mode is meant for multiple playthroughs, that’s where you get your practice. They give you more than enough to keep them fed. Pro tip, you won’t really need more than 3 charges each if you have multiple Guardians.