How can I connect to an external monitor and charge my Macbook Pro with one wire?

In general the cleanest solution to achieve this is usually a USB-C/Thunderbolt 3 monitor. These connectors not only have capacity for the video signal, but also feature power and USB passthrough to the MacBook.

If you don't have a USB-C/Thunderbolt 3 capable monitor, you would need to get a separate USB-C Hub or docking station. They usually not only feature a video output (usually HDMI), but also USB and SD card slots, sometimes even Ethernet. Yet, be careful: although USB-C is fast (5Gb/s) it is limited, i.e. if you connect 3 external SSDs, a 4K monitor and want 1Gb/s Ethernet, that's obviously not going to work.

You mention you have an ASUS Pro Art display. Without knowing the exact model, on ASUS website they are all featured as either USB-C or Thunderbolt 3 capable, so you should actually be able to only plug one Thunderbolt 3/USB-C cable into your M1 Mac and be ready to go. Some of them even feature a USB-Hub, which means there are some old-style USB-A ports on the monitor which will also be passed through via the USB-C/Thunderbolt connector to your MacBook. Even further some allow daisy chaining, so you can connect another Thunderbolt device to the monitor and use that as well.

Read more about the difference between Thunderbolt 3 and USB-C.

Any hardware that supports USB-4 or Thunderbolt 3 will work. In general, you can have some devices that draw more power than your hardware, but the M1 Air and Pro draw so little power, I don’t think anyone has shipped a display or dock or hub that won’t fully power the 2020 M1 hardware lineup.

The Intel Macs that use Thunderbolt 3 can draw more power than a lot of docks/displays provide, so they work as long as the internal battery can make up the difference between whatever power the dock provides and the shortfall based on current power budget. If the Mac idles, the dock should keep it running 24x7 even if the hub is 60 W or lower since most Macs idle less than that.

As for vendors - I have had excellent results with:

• CalDigit
• Sonnettech
• OWC
• Belkin
• Elgato
• Dell (be sure you check video capabilities, many only run 30 Hz)

I have had very bad results with other vendors I’m not going to name at present so be sure you understand what your warranty and return policies if you buy any brand, especially one not listed above. Some people are fine with inexpensive docks or low refresh rates, others want to launch those accessories into orbit when they realize they could have had 4k + 60 Hz and years of use from a dock had they shopped around a bit and not bought the cheap one.