The primary collection of pieces you are looking for is titled 24 Studies for Guitar (also known as 24 Etudes) by the legendary Brazilian composer and guitarist Sérgio Assad.
In the current classical guitar landscape, there is a crisis of relevance. Many young players can play Recuerdos de la Alhambra perfectly, but they cannot swing. They cannot improvise a levada (rhythmic groove). sergio assad 24 studies
Aesthetic Preservation: While many pieces use standard tuning, Assad occasionally permits himself the liberty of retuning (such as an F or D on the 6th string) to capture the depth of the original piano masterpieces. The primary collection of pieces you are looking