There is no “currency type” but…
New cell style, most likely derived from the Deafult style, and only choose the tab
Numbers. There select the wanted format or create your own code.
Later apply this CellStyle to all the CalRange_s where you want numbers to be shown as currency amounts.
Also: Please note that the usage of the comma and of the point as well as a “Group Separator” (often called “thousands separator”) is explicitly deprecated by international standards.
Also: Always express the sign of a negative numeric value by an actual sign. Don’t use a color or parenthesing for the purpose.
LibreOffice doesn’t speak VBA, but it has a powerful API.
To apply the new CellStyle to all the cells of a SheetCellRange object simply assign:
myCellRange.CellStyle = “myCurrencyStyleName” placing your actual style name in the proper position.
A single cell also is accepted as a range object.
In rare case yo may want to avoid the usage of a named CellStyle. I would dissuade from such an approach, but it can be done. Come back if you need additional respective help.