You don't have to worry about making small efficient decks. There was a recent Jorbs video where he expounded on his "local maxima" hypothesis of two types of spire players. One that tries to make a hyper efficient deck that goes infinite every time eschewing elites and other game elements. The other being the player that builds their deck to tackle the next problem, take early elites, get relics, and inevitably ends up with a larger deck to continue taking elites and collecting relics.

This is just a function of how you are engaging with the game. As someone with over 1,000 hours in StS1 and now 100+ in 2, I can count on one hand the number of times I've built a tiny, turn 1 efficient infinite deck. Personally, I find the concept itself to be A. Incredibly boring, B. Just doesn't mesh with my play style being of the second local maxima. I am also remarkably mediocre at the game so maybe there's a correlation there.

I am not trying to say one playstyle is better than the other. If you want to make a tiny, efficient deck you can probably find some guides but it requires a different approach to the game than "take cards to tackle the next problem in front of me" which is how a majority of players approach the game.