cant find microphone isolation mode on my iphone 15 pro even in a call

See if the information here helps. Use Voice Isolation, Wide Spectrum, or Automatic Mic Mode on your iPhone and iPad - Apple Support

In addition to pulling down the Control Center, you also then have to tap Phone in the top which will open up microphone settings.

BD1989 wrote:

Perfect! That thing at the top is so small I missed it over and over again! Thank you, Zacchy!

No worries, you’re very welcome!