I don´t mind that there is only one currency and it is normal that you have tons of money at the end of games.
The problem with BG3 is that you have tons of money at the beginning of the game. Especially if you give a merchant some stuff for free to max your reputation, give all items to the char with the highest CHA and cast guidance before shopping. Most players have no problem to buy all unique magic items in the game and still have tons of money left. Maybe the game is "Larianized" in a way that economy is balanced like in DOS where you have to get new equipment every level but DnD is not made that way. In DnD magic items are supposed to be rare and once you find them you will probably use them for a long time.

Prof. Dr. Dr. Mad S. Tist

World leading expert of artificial stupidity.
Because there are too many people who work on artificial intelligence already