VLC has been marked '4K' ready since version 2.1 (See:
https://www.videolan.org/vlc/releases/2.1.0.html). A brief test with MacOS X 10.12.5 and VLC 2.2.6 on a 2014 MacBook Air, shows that an MPEG4 video (4096x2306) using H264 works well, but an MKV video (3840x1632) using H265 stalls, as does another MPEG4 video using H264. This was a quick test with some videos I was able to find.
The limitation is more likely to be the processing capability of your Mac, than VLC, though more recent versions of VLC are likely to be more optimised for any given scenario, but it will unlikely help if you have weak hardware.
Providing logs, messages, configuration info (VLC, OS, Hardware) and a clear explanation of the issue always helps the problem solvers help you, even if they don't end up solving the issue. Just think what you would need if you were solving someone else's problem. Additional: Always looking for eager and capable MacOS X developers to join the VLC team - for more information
see here.