PSA: USB-C is not Thunderbolt. Yes, you know this already. I know this already.
Yet I spent an hour or so just last night trying to figure out why I was having trouble connecting two Macs before I remembered. The error message was something like "Use a Thunderbolt port..." and as I was only half paying attention, I thought, "Aren't they all Thunderbolt ports on this M1??", then I spent a while swapping dongles around and then swapping USB cables, then looking at support pages, then I finally thought, "You idiot." and ordered the right cable. Don't be me.
Yet I spent an hour or so just last night trying to figure out why I was having trouble connecting two Macs before I remembered. The error message was something like "Use a Thunderbolt port..." and as I was only half paying attention, I thought, "Aren't they all Thunderbolt ports on this M1??", then I spent a while swapping dongles around and then swapping USB cables, then looking at support pages, then I finally thought, "You idiot." and ordered the right cable. Don't be me.