Quick note: under Ubuntu 20.04, VLC’s performance can be greatly improved for x264 codecs by changing the default setting: Tools -> Preferences -> All -> input/codecs -> Video codecs -> FFmpeg -> Hardware decoding -> VA-PI video decoder. Note: not “VA-PI video decoder (DRM)“
This applies to VLC 3.0.x on Ubuntu 20.04. An annoying side effect is that VLC leaves a tray icon even when closed. I know no solution to this other than killing the process.