OK, This will help many concerning Mac and the XR382CQK Acer Monitor:
Here's my setup:
OS 10.13.1 High Sierra
2016 Macbook Pro 15" (with touch bar)
Acer XR382CQK 38" curved Monitor
If you have anything different than the above, this may be helpful, but may vary. Other 2015-2017 MacBooks should have similar results as detailed below though.
From the box, I attempted to hook up my new Acer monitor using the thunderbolt power cord that came with my MacBook since no USB-C or USB-C type cable came with the monitor. All I got was 6 dings from the computer as the monitor attempted to cycle through all of its possible inputs. I spent a couple of hours attempting to adjust any and all monitor and computer parameters to get it to work. Nothing.
I was able to get the HDMI to work through an HDMI-to-USB-C converter plug, but the refresh rate was only around 30 Hz at highest resolution. I also was able to then plug in the MacBook Thunderbolt cable from the monitor into a second port of my MacBook to get the power charging to work in tandem. I did this for around 3 days which worked perfectly, but one reason I got this monitor was to eliminate cables. Then I had a thought. I re-read the Acer installation manual and it said to use a USB-C CABLE (not thunderbolt)! I was using a Thunderbolt cable. So I bought 2 different USB-C 3.1 cables to see if they would work. YES IT DID! So Friends, go buy yourself a Veckle B071XSDH9D USB-C 3.1 Gen 2 cable (or probably any 3.1 gen 2), and utilize the TOP Acer resolution at 75 Hz refresh like me. This cable also charges my MacBook at the same time. Finally! What a pain. I think the thunderbolt & USB-C details out to the general public are really not clear, and why all of the confusion is out there. Enjoy! I love this monitor! Also, get BetterSnapTool app to snap your windows around. This setup COOKS!