I do believe that’s correct 
Just a general warning that beta plugins have not been tested or vetted in any meaningful way, and often don’t have a nice UI.
There has been some brief discussion on this Apparently, there has been some effort to build SurgeXT as an LV2 plugin, but there are some unspecified issues that prevent it from working as expected. Unless a plugin can be built as an LV2 plugin, it won’t work on a MOD unit until support for other plugin formats (VST, CLAP, etc.) is added.