Macbook Pro headphones port won't pick up my microphone
Solution 1:
USB Audio Port Adapters usually work well, but I'd look for "compatible with Mac" in the description just to be sure. Why your TRRS adapters are not working is kinda weird, possibly dust? After seeing the video - doing exactly what you are doing (but with a lavalier mic) does work for me. I can only recommend to check for dust or try to use a different adapter. There are also adapters that are not splitters (they only do mic to 4pin), try getting one of that kind.
(Don't have enough reputation to comment, which is why this is an answer)