I just signed up to say that the answer by Monomeeth is almost certainly incorrect.
The "Hub+" and "Arc Hub" definitely will not work because to charge the device, it will need 1x USB-C to MacBook, 1x USB-C to charger, and a third USB-C to connect to the USB-C monitor. They only have 2x USB-C on the adapter.
The "Kadi Port" might work, but it is highly doubtful, because it has another HDMI port on board. Aside from HDMI requiring active protocol conversion from DisplayPort (adding to cost and complexity), that would also require that there be a DisplayPort MST hub inside, and for the cost, that is highly unlikely.
I am interested in solving this, because it will allow me to use it with my Galaxy S8 / S8+ on the go without draining its battery.
I have a heap of USB-C female breakout PCBs that I ordered off Ebay. When I get more time, I will connect four of them together. It will be that the two main ports will be connected together with all pins except power and CC (TX, RX, D+, D-, SBU). The power and CC lines will be connected to their corresponding charging ports. I don't know if it will work, or if it is safe. But I am getting desperate. I cannot believe that not a single company has identified this niche market. I have looked extensively.
I have solved the problem of how to connect a normal DisplayPort computer without USB-C to the Asus MB169C+ - but it is not pretty. It involves using a Sunix UPD2018, and building an enclosure to power it through the PCIe x1 bus - tested and proof of concept on YouTube. But this does not solve the power problem.
I am sorry, but to the best of my knowledge, the correct answer is, at least for the time being, that there is no solution.
Best of luck!