I thought that LMMS 1.2.1 could load LV2 instruments, not sure where I got that from, looks like I'm wrong.
I just read
LV2 plugins in LMMS with CARLA -
Summarising my understanding of that thread-
LMMS needs CARLA to host LV2
CARLA may or may not appear after install depending on your distro (its an old thread, maybe your LMMS version as well)
Native LMMS LV2 support is scheduled for LMSS v1.3. From git - This is a first minimal Lv2 plugin, supporting the whole core, except for CV ports (aj automation?) No features or extensions are supported yet.
I hoped that adding a new ZynAddSubFX would be easier. I'll return to learning about LMMS. Maybe look again when 1.3 is released.
I have some C++ Windows experience but no qt