Do I need a special motherboard to mine Malairte?

No, you do not need a dedicated mining motherboard for a typical home setup. Any modern consumer board with one full-length PCIe slot is enough to start mining Malairte with a single GPU and your existing CPU. The dedicated mining motherboards you see online, with six or more PCIe slots, were built for the Ethereum era and are overkill for most home miners. If you plan to run two or three GPUs in the same machine, look for a regular ATX board with two physical x16 slots spaced at least three slots apart, and at least one extra x4 or x1 slot for flexibility. B550, X570, B650, and X670 boards on the AMD side, or Z690 and Z790 on Intel, are all sensible choices. Avoid the cheapest entry-level boards as their VRMs are not built for sustained load.