I thought I could use a USB type C to HDMI cable that I already had - but it doesn't work. The macbook detects it and appears to think it's using it as an extended display but the monitor doesn't respond. I suspect it's a samsung g9 thing rather than a macbook thing so I'll do some more research! I might just need a better cable rather than the cheapest one amazon sell
edit: oh wait, there we go - just needed a reboot... it doesn't support the full horizontal resolution but you can split the screen in half with the monitor's PiP and use it as two screens with 2 cables.
Thanks for the tips - to be honest I thought the lack of ports would be a problem but over the last 2 years though I've gotten used to using a mixture of desktop, tablet, phone and laptop for work so almost everything that would have previously needed a port is now available wirelessly (storage, printers etc).