Hi Jens, I had the same question. The answer is to get an adapter so you can plug it into the XLR microphone input on your Mackie.https://www.digitec.ch/en/s1/product/rde-vxlr-microphone-accessories-3498037
Here is what I have tried:
L = Rode Lavalier
W = Rode Lavalier + Rode Wireless GO
LI = Line-in (using a 3.5mm-6.3mm adapter)
HZ = Hi-Z / High Impedance / Guitar (the Mackie 12FX doesn't have this, but the Mackie 402VLZ4 and many other mixers do)
MIC = microphone XLR input
L + LI: No signal, even with all the mixer knobs turned all the way up.
W + LI: Faint signal, can hear it with all the knobs all the way up if it is right in front of my mouth, but not if it is on my shirt.
L + HZ: No signal, even with all knobs all the way up.
W + HZ: Works on shirt, with knobs (gain + level) turned way up to "3:00" position, but sound quality is not great. It sounds like the mic is under a pillow.
L + MIC: Works well with knobs at central "12:00" position. Noticeable background hiss.
W + MIC: Works well with knobs at 12:00. Good quality.