videohelp[.]com/software/Media-Player-Classic-Home-Cinema
Playing video has gotten a LOT easier over the years, with loads of players, many including display tweaks to get the most out of your hardware. Saying 8K, or 4K for that matter, means little for a software player -- the size of the video frame means almost nothing to the player, which simply decodes the audio & video, sending the results back to Windows to display the picture and produce the sound that you hear. [Hardware can be different, e.g. a streaming player like the FireTV might have a specific HDMI requirement.]
Where does the 8K player go wrong? It fails to open/start a Blu-ray disc, and crashes when fed a folder with the contents of a Blu-ray disc. The Only advantage it *may* have had is that some players out of China handle a Blu-ray's DRM -- none of the free players like VLC or MPC-HC will -- though the product page on Dimo's site was silent on that feature. [I guess their silence makes sense, since if it can't play a Blu-ray disc, managing the DRM on that disc is irrelevant.] PowerDVD Ultra works well, but it's not free. If you remove the DRM first, most of the free players will work OK, though the menus & such won't be displayed. MPC-HC stands out because it has a lot of tweaks, if you want to bother with them, and has a frame by frame step button for screenshots etc., which can be a PITA with VLC. Leawo's player handles DRM [how well I can't say], tries to manage the menus etc. if you install the Java runtime, & has a paid version, but has grown significantly in terms of bloat.
Dimo's 8K player also is a bit of a hog, adding all sorts of registry entries to associate all sorts of media types with the player. Leawo's player at least has a switch to Not do that. Otherwise you get a C:\ProgramData\fltk.org folder, plus C:\Users\ [UserName]\ AppData\ Roaming\ ivscat.com, cat-video-player, and fltk.org folders. There's no easy way to reverse the changes to the registry associating all those types of media files with the 8K player, though you can remove the uninstall entry: [HKLM\ SOFTWARE\ Microsoft\ Windows\ CurrentVersion\ Uninstall\ 842F0D80-2EC4-4903-9798-714D9927DCA1].