The newest kid of the block is USB C, as I'm sure you are aware. Assuming your future PC will include a USB C socket, you might have to look into whether you can buy a firewire to USB cable. Alternatively if you are building a tower PC you could always fit a firewire card.
Next question, which I can't answer, is whether you would need Windows drivers for your Mackie that are compatible with Windows 10 or 11. Back when your Mackie was new, getting gear to work could be an absolute head-banging nightmare, because everything needed bespoke drivers. These days everything's class complaint and it's all just plug n play, even in the Windows world.
Lucky I saw the question tbh because it's not ASC related.
