Denon SC Live 4 Latency Issue

Hi everyone,
I’ve had the SC Live 4 for almost six months now, and overall I’m quite happy with the value for money. The standalone functionality was especially important to me, and the built-in speakers make my home setup really simple and convenient.
However, I’ve been struggling with a major problem for quite a while now, and even after doing a lot of research, I still haven’t been able to find a proper solution.
I have several synthesizer apps on my iPad that I can control with a MIDI controller connected via a USB hub. These synth apps support Ableton Link and they also connect to the SC Live 4 via Ableton Link, so in theory everything runs in sync.
Now I’d preferably like to route the audio output from the iPad via Bluetooth to one of the decks on the SC Live 4 — and that’s where things start to go wrong. Bluetooth introduces a clearly noticeable amount of latency.
Apparently, there is no way to eliminate this latency. The only alternative seems to be connecting the iPad to the AUX input of the Denon via cable. But then I have another problem: I can’t route the iPad audio to one of the actual decks.
It’s really frustrating. I don’t understand why Denon designed the AUX input in a way that prevents you from simply assigning it to one of the decks.
Or has anyone found a way to reduce the Bluetooth latency to virtually zero through some setting on the SC Live 4?
Thanks in advance for any helpful advice!