Question about Sharkoon TG4 RGB

Yes, you can, the mainboard is in ITX format (dress size S) and mainboards up to ATX size (dress size L) fit in the case. In between, there is still mATX (dress size M). And yes, your mainboard also has only connections, as you can control all the enclosure fans via a single fan connection (or even without a connection directly to the power supply unit).