“The metals used in the temple have symbolic meanings for the Levitical priesthood (the priests of Israel descended from Levi). What does gold mean, Levitically speaking?”
Gold is holiness.
The objects in the Holy and the Holy of Holies of the Temple and Tabernacle were either gold or thorn bush (acacia) wood overlaid with gold (Exodus 25). Some of the priestly garments were made of gold or had gold embroidery (Exodus 28).
The magi brought Jesus gold, incense and myrrh. Gold was for his deity. The others were for his other two job descriptions, priest and prophet (Matthew 2:11).
We need the holiness of Christ to be truly rich (Revelation 3:18).