A custom built will yield the most power money can buy, no doubt. However as you’re beginning the process of home studio creativity, and learning which daw,which software etc. adding on the PC building component would be foolish.There is more to know and learn when it comes to PC building than anything else. Your best bet would be to buy a custom music PC from a reliable maker. In a couple of years when you’re ready to move up to a more powerful PC ,then you might look at building your own.