I think that part of the answer can be found in the release notes:
https://github.com/LMMS/lmms/releases/tag/v1.2.0-rc8
Known issues with this release:
Apple
* VST plugins (.dll) do not work on Apple (Please see bug #698)
In theory macOS users can install wine using Homebrew.
In practice, wine support would be needed inside the LMMS app on macOS and I don't think that's coming in 1.2.0.
There are other VST audio plugins for macOS and perhaps someone knows how they can be used by LMMS.
VST plug-in locations on Mac OS X and macOS
https://helpcenter.steinberg.de/hc/en-u ... 5000171310
/Library/Audio/Plug-ins/VST
/Library/Audio/Plug-ins/VST3
Using AU and VST plug-ins on Mac (ableton.com)
https://help.ableton.com/hc/en-us/articles/209068929
/Library/Audio/Plug-Ins/Components/ (AU)
/Library/Audio/Plug-Ins/VST/ (VST)