Onkyo apparently is known for HDMI board failure. Denon had a screen failure problem in 2013 across the board. That leaves Pioneer and Yamaha.You could bypass the receiver and hook right into the monitor then either use a monitor audio output (I don't know if many have that or not) or use optical out from your sound card/motherboard to the receiver. After a quick glance it looks like you are going to spend $600+ for a receiver that has 21:9 pass-through.
Onkyo USA Corporation
You can see how I have it set up right now above. This issue didn't occur because the TV out was to the 3008WFP running at 1080P. It bugs me that there's no 21:9 for some reason. Come to think of it, I am not sure if any receiver supports our 3440x1440 or 3840x1600 (not that anyone will appreciate it at TV viewing distance). I find it kind of funny that this receiver supports 4K and would even upscale, but it can't handle PC 16:10 or the 21:9