[ajamils]

ajamils, have you tried the method here using official KODI with MPC external player coupled with LAV Filters and madVR or have you always been using DSPlayer and adding an MPC player to it?  I think some of your problems are DSPlayer problems exclusively and not inherent to both.  Given the severity and length things have been problematic, it would be worth a try if you haven't already.  Regardless of adding any KODI as your front end, were you able to get things working proper when stripped down to the basic Windows Explorer level?  If not, are you concluding madVR and/or KODI are making playback possible where Windows Explorer alone could not? 

No, I have not tried using Kodi with MPC. In the past I had always only used Kodi's built-in player. I just recently came across Kodi with built-in DSPlayer and been trying to get it setup as the default player. I do use MPC-BE/HC to test out files outside Kodi. 

I have given up on trying to make everything work at the level I was originally trying to. I think my main issue is that I'm using mkv rips of 3D movies which are not 1-to-1 frame packed version so neither MadVR or any other player recognizes them to automatically enable 3D mode. To make matters even worse is that I have 4K HDR, 1080p, 720p and SD movies in my collection so I want MadVR for up-scaling and HDR pass through. 

For now the only solution I've found is to keep my desktop resolution at 1080p/60 and use DSPlayer in Kodi for everything except 3D mkvs. For all movies, DSPlayer +MadVR upscales to 4K and when I want to watch 3D movies, I just use Kodi's built-in player which show movie in two images and then forcing my projector to 3D-SBS mode makes the movie into 3D. This solution is only possible if the resolution is at 1080p/60, hence the reason for keeping Windows resolution at that. Not a perfect solution but I got frustrated trying to make everything work.