It’s just a trs to trrs adapter, right? If so, there are several that a search will show, such as:

https://smile.amazon.com/Valley-Enterprises-4-Pole-3-5mm-Female/dp/B00C4FU52C/ref=mp_s_a_1_8?dchild=1&keywords=trrs+adapter&qid=1586714690&sprefix=trrs+&sr=8-8

And

https://smile.amazon.com/Movo-MC3-Microphone-Adapter-Smartphones/dp/B01N9CJDVE/ref=mp_s_a_1_1_sspa?dchild=1&keywords=trrs+adapter&qid=1586714833&sprefix=trrs+&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExT1dGQVIwSjdQSTAmZW5jcnlwdGVkSWQ9QTAyNzc3OTVBSENGVFpZQzhUMlYmZW5jcnlwdGVkQWRJZD1BMDg4Mzk5NlVHS1ZESjNHRTIyTCZ3aWRnZXROYW1lPXNwX3Bob25lX3NlYXJjaF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl