Facetime Audio using Audio Interface

I am wondering if someone can help me with this:

Here is my set up:

I have an Imac running Catalina 10.15.6

I have a Steinberg UR44, audio interface .

My goal is to get the best sound possible out of my hardware, when Im play guitar on Facetime for others .

Here is my set up:

I plug my electric guitar into Input 2 at the front of the UR44.

I run Logic as my DAW, which I use to add effects to my guitar signal (plug ins for distortion, delay etc). I also load a backing track in Logic, which I play to. So, in essence, Logic is spitting out two pieces of audio 1) the backing track, and 2) my guitar playing over top of it.

I send one of the headphone out jacks, to Input 3 on the front of my UR44, via a 1/4 patch cable. (I am sure there is a better way). Doing it this way sometime gets me a whistling sound, or sometimes a sound that sounds like it has effects on it. In other words, not a very good sound. Certainly nowhere near the sound quality i know the UR44 produces.

I use a software product called OBS, which basically enables me to tp use my Ipad as a camera, for streaming video to Facebook Live.

Streaming the audio component is what i need help with.

I find that the guitar signal is sometimes too high in volume for the backing track. I also find that i can't make the backing track loud enough.

Forgetting about what i said about my set up, how would you go about setting it up for Facetime? How would you rig things up?

Thank-you