honestly , i have been down that rabit hole and after all the hasle with carla and other apps to be able to use vst3 etc,,, I came to the realisation that the native instruments on lmms are already the best...did you use sf2 yet ? sf2 is cool , yu download soundfont packs and put them in the correct folder , the ou drag sf2 into playline , click it open the file select menu then choose a soundfont , then simply by rolling mouse wheel where it says "patch" to change through all the different instruments in there , much easier than zynadd.... Here's a cool tip. Get "Neuralnote" , you open that app, drag a song into it and then you can play around with the settings and then just drag from the "piano roll looking area" to anywhere you want it to go and just like that it transposes your song or sample to midi ( it ignores drums) this midi you made can be imported to lmms , you go into it in piano roll , "ctrl+ a" to select all notes then click copy. now drag sf2 into playline editor , open it in piano roll and paste , then go back to the sf2 gui and simple choose an instrument ,,,, you can take a piano melody's midi and use any instrument on that... from church organ to bagpipes .... sky is the limit . Lastly if you have amelody in your head and you dont know how to get it into lmms , you can simply record yourself humming or whistling it , sing if you want ,,,drag that to Neur... and there you go,,,