I understand that bitcoin-qt -prune=6000 or prune=6000 in bitcoin.conf means that the last 6000 blocks will be saved, as it synchronizes the old ones are deleted, always leaving that number. When you start the node for the first time I think it saves 500 blocks, I don't think it's bad that it's 14GB for that number of blocks.

Save your time from reading this one. TLDR: pruning still works, but one user didn’t understand pruning limits (pruning only applies to the chain, not the other files derived from it, like the UTXO database).