how do I separate mic input and speaker output on my iPhone 11? Need mic input and speaker output

Hello! I need to separate the mic input and the speaker output on my iPhone. In-ear audio (headphones, AirPods) are not an option for me and I’m finding I am straining my voice using speakerphone all the time. I would like to use a separate microphone (like a lavalier clip-on) to speak and my phone speakers to hear the calls I’m on. Would prefer iOS solution? But open to buying app or addl hardware to make it work. Thanks!