I've preordered an M1 iMac, but I'm confused about how to connect my existing monitor to it. The monitor I have can display 4K@60hz either via DisplayPort or HDMI. With my current Intel iMac I'm connected via Mini DisplayPort to DisplayPort cable. Is there an adapter I can buy to keep using that cable? If not, what kind of cable should I buy to connect at 4K@60hz? I'm so confused about USB-C / Thunderbolt!!