Question / Help Help with Taking Calls with iPhone for Stream

Good day,

If this has already been solved please point me in the right direction.

I want to take a phone call from my iPhone 11 PRO MAX on my stream. This requires getting audio out and back into the phone through the Lighting port. Since my Apollo x8p does not have a lighting port for easy connectivity to the iPhone I'm having to figure out the proper sequence of adaptors to make this all work.

The idea is this:
Audio to macOS: iPhone 11 PRO MAX --> lightning - 3.5 TRRS adaptor --> Headphone Mic Y Splitter --> HEADPHONE side to Apollo x8p --> (DAW, Headphones, and OBS).
Audio from macOS: Apollo x8p out (line level) --> Direct Box using a -20db pad (i've also tried -40db) to convert to mic level --> MIC side of Y Splitter --> Lightning to 3.5mm adaptor --> iPhone 11 PRO MAX.

I get audio from the phone just fine. The common trouble though is getting audio back into the phone: seems like this is an issue everyone has but .

I have bought and returned several CTIA compatible splitters with no success through the mic side of the splitters: at least four different splitters: UGREEN, two different MilSO, and a DUKABEL. I have been careful to ensure they were labeled as CTIA standard and that the receiving sides are TRS. Thinking this was an issue with the CTIA vs OMTP standards I bought a converter to swamp the ground/mic signals and that still didn't work. The only thing I've been able to get to work is the BOYA TRS to TRRS mic converter (link below): this will bring the audio from my interface back into the iPhone HOWEVER while it would work for recording audio into the phone (such as for music and such) it doesn't have a headphone out to get audio from the iPhone over to my stream: i.e. the only way to make it work was in the following configuration: apollo out --> DI box --> BOYA mic Adaptor --> Lightning to 3.5mm --> iPhone and thus no headphone can be plugged in.

I did try the MOVO TCB3 and while it works the connections are loose and the audio cuts in and out resulting in static and bad quality. This however tells me the concept works and all my audio routing is correct and the issue is rooted at the Y Splitter. I did have access to a Tascam Model 12 and confirmed again the concept works and good audio can be achieved. The Tascam Model 12 has a feature where you can use a TRRS cable and connect the iPhone directly to the mixer.

I also had access to an iRig2 which "works" but the audio isn't as good as I want.

Have any of you solved this problem? If so, what Y splitter did you use (link please) or if you went about it a different way please do let me know? I'm to the point where I'm thinking I just need to break out a soldering iron and DIY this together.

BOYA Mic to TRRS adaptor the DOES work with iPhone. I have used SEVERAL including one by RODE and this is the ONLY one which works with an iPhone 11 (as of 16MAY2020) -- so for getting audio into the phone GREAT but for those of us who still need a headphone out from the phone it's not going to work.
I got it! After weeks of pulling my hair out. My issue I believe is the audio interface outputs a BALANCED line level signal and the iPhone mic apparently will only accept unbalanced input — and, as far as I can figure, when you input a BALANCED signal into an UNBALNACED input the iPhone balks and doesn’t recognize anything. So I reversed the input and outputs of my Rockville RDI5 Direct Box and it worked. My set up is now:
Audio Interface —> DI Box (balanced side) —> y splitter (from unbalanced side of DI box) —> y splitter (CTIA standard) —> Lightning to 3.5mm adaptor —> iPhone 11 Pro

The DI Box referenced is the Rockville RDI5