Andorra is a tax haven (ironically also used by Jordi Pujol who was KRLS's predecesor for 30 yrs) that is why they don't support. Because you also have the concept of Paisos Catalans which is a claim to territory on the basis of language, to unify all Catalan-speaking areas as one country (not only Catalonia as the territory of the (fmr) autonomous community, but also Andorra, the French department of Pyrennes Orientales, La Franja del Ponent in Aragon, all of Valencian Community, all of Balearic Islands and one town in Sardignia called Alghero), driven by left-wing parties (mostly ERC & CUP) as a response to Franco.
However this idea is also VERY controversial:
1) The French Republic is one and indivisible. What if a Catalan Republic claims territory against the French one. Even more worrying - Pyrennees-Orientales has been put under a new region as part of territorial reforms called Occitanie, without any reference to the identity of Pyrennees-Orientales as Catalans. So there have been protests in the main city of that department: Perpignan, requesting to be called Pais Catala. So imagine if the Catalan Republic claims to defend their rights as Catalans?
2) Paisos Catalans is also controversial in other Spanish autonomous communities, but especially the Valencia one. The idea itself came from an author called Joan Fuster, born in the territory of what is now Valencian Community. His idea was that the flag of the regions of the Kingdom of Aragon - the senyera - is essentially the one single flag - For a single country/state. So what happened in Valencia was that they didn't know what to call their territory after Franco died during the Transition. They had various choices, each reflecting a different stance towards Spain and Catalonia: Kingdom, Land, Country, Community. They settled on Community as the most neutral position and with what is the system of autonomous communities in Spain. However, this was after a big fight over the symbols of the area, particularly the regional flag. You had a movement called, blaversime, which refers to the blue stripe in the hoist of Valencia's flag. Essentially, the City of Valencia's flag is used to represent the entire community. But all this comes from history, Valencia was conquered by Jaume I from the Moors, but instead of annexing to either the Kingdoms of Aragon or Catalonia, he made it its' own Kingdom under the confederation of the Crown of Aragon. So Valencia has its' own Generalitat and Parliament, like Catalonia does. But they are very loyal to Spain, owing to their being (varyingly) anti-Catalan.