Not an expert either but I would check your extension cable. If you have headset with mic and it has only one jack out, you want to use extension cable that has at least 4-pins / 4-poles as that 4th pin is for microphone. Look how many black "bars" is there on your extension plug: 2 bars = 3-pin, 3 bars = 4-pin, etc.

You want something like this https://www.amazon.com/dp/B07QN65DJ6/. Then you should be able to run splitter off of it or get a long ass splitter.