The general advice from smaller scales is to use DC for points/switch/signal motors etc. and keep DCC for locomotive control.
I would have multiple controllers if you want more than 1-2 trains running at the same time and expect to control
them (my father just has a double controller, and switching between three trains can be exciting - it's also a bit of a pain
if you want to temporarily stop a train, control another one, and then switch back to the first one

). The nice thing
with DCC is that you get to drive the trains rather than the track, and you can get more operational flexibility.
The rationale for using DC for accessories is that the DCC point/accessory decoders are expensive, you can need quite a lot of them
(I have about 50 points on my layout in the attic), and they can be a pain to control
(e.g. if you need to remember a code number for each point). Much easier to just have a DC switch box and a CDU. That way you
can dedicate one switch to each motor, test the wiring independently etc.
The exception is that if you want to automate absolutely everything using computer control, then DCC is simpler. But I haven't seen
many layouts like that (even at exhibitions).
For what you're proposing, the main thing is to make sure you don't mix up AC and DC. The output from the DCC system (Massoth) is
an AC supply at 20V or so. The input to the switch unit (LGB) will probably be AC (either 20V or mains - don't get this wrong, of course).
If it's 20V AC, then the Massoth unit may have a suitable output that you can use (which is what people in the thread are suggesting).
The output to the switch motors will then be DC at about 20V as it was on the original layout. Apologies if this seems to be teaching
you to suck eggs, but electrics can be a pain if you get things wrong!