Edit - sorry, this is a bit 'stream of consciousness' with some guesswork, but go with the flow & see where you get ;)
Still hunting for why you don't see controls in fullscreen, but in the meantime here's your bonus...
Note: VLC must always be quit & relaunched to show changes.
Prefs > Show All > Interface > Main Interfaces > macosx > Resize interface to the native video size ... uncheck.
This will keep the initial playback in the same size window as your Playlist.
tbh, I'm not sure what you mean by 'frameless', but I'm assuming for some reason you're not using the regular Fullscreen toggle, F.
Maybe that's all it is, use VLC's fullscreen, F, not the macOS fullscreen [which in VLC if you click the green dot is the old 'fill the window as far as it will' rather than true fullscreen]
Ah - I just discovered ... basic prefs > Video > Use native Fullscreen - switch that off unless you want your second monitor to go black
Btw, the rather glaringly obvious "Show fullscreen controller" in my image appears to do absolutely nothing. I get the fullscreen controls if I move the mouse, whichever way that is set.
OK, my best guess is you're running with Window Decorations off.. which is horrible, it floats the video out on its own with no apparent method of control.
Try this instead for all of the first 2 blocks of that pref pane...
That will make it playback inside the same window as your Playlist, will keep the regular controls underneath, then when you go to fullscreen, will only show them when you move the mouse. It will also still let you use a second monitor whilst full screening in the other.
Late edit - I eventually figured it out - when you're in Frameless [Window Decorations off] then your controls are still at the bottom of the playlist window.