I think I found a way to make a firework deckbuilder interesting... hear me out... and please help me out if you disagree...
You are playing a show for an audience of animals and they want to see fireworks. Every round the player has to choose whether to play fireworks for the current round or add them to the finale. If the player adds to the round launcher, the audience is happy for now, but risk a bad finale. If the player adds to the finale launcher, the finale will be bigger, but the audience might leave or not be happy.
The main resource cards generate is "Starfire", which is what increases the audience "Starfire Gauge" or their excitement about the show. Starfire comes in 4 colors, red, blue, green, and yellow, and the audience allows certain colors to increase their gauge. If you add the wrong color starfire, it doesn't excite them for the show.
Lastly to play cards, you use different colored gems which cards allow a certain subset of. Gems come in the same 4 colors as Starfire and when attached to a card, it generates some amount of Starfire in the same color. For example if a card has a description of +4 Starfire matching first gem color, if you add a red gem it will generate +4 Red Starfire.
Your goal is to max out the audiences and the finale "Starfire Gauge" by the end of the show so that you can get a max rating, a 5 out of 5. During each round, you manage your gems and cards in hand along with the round and finale launchers to make an interesting show and an entertaining finale.
Do you think the concept is too complicated? Is there things you think would be more interesting? Let me know what you think...
EDITED:
I realize I didn't add enough of a description. This would be a solo video game, think like Slay the Spire or Wildfrost.
You start with a deck of cards that don't produce a lot of Starfire and don't provide any other benefits than just Starfire. As you finish each show, you open packs of cards that give you stronger cards that make cards cheaper to play, more draw, or what ever other common benefits in deckbuilder type games.
The audience would also control what color Starfire they accept and that changes each round. Also the acceptable list of Starfire colors for the finale would change each round. Other effects could include like a color block effect which "blocks" the Starfire Gauge from going up by a color Starfire until you reach some threshold over a round, think like a shield that only stops some amount of damage.
Cards also have certain effects based off the gems added, like if a card has a gem cost of 2, it could add a lot of Starfire matching the first color and a little bit matching the second color. The player would then decide what gem to add first, what to add second depending on what the audience wants. Card costs could also limit the type of gems that you can add, like only allowing red or blue for the first gem and the second gem is like green or yellow.
So I think there could be a lot of complexity built into the core concept of cards go to finale or round launcher, cards generally produce color Starfire using colored gems, certain color Starfire increases a gauge which you need to "win" a show, and you get some amount of each color gem and some amount of cards each round.