DDR5 motherboards should come with only 2 dimm slots as

As DIMM slots are known to have separate contacts on each side of the circuit board, the size of the data path doubles when compared to SIMMs

More DIMM slots provide flexibility for future upgrades, allowing you to add more memory without replacing existing modules If your motherboard has fewer slots

dimm2 slot A DIMM slot is like a parking spot for memory modules, which houses and connects them with the motherboard

dimm slot meaning DIMM slots of the same colour indicate different channels In the figure, DIMM1 and DIMM3 are on channel A, whereas DIMM2 and DIMM4 are on