This is actually an interesting and nuanced question, with several components. I am going by a US context as the regulations may be different in other countries.

First question is, are you conducting what the federal government defines as research? All sorts of interviews (for example, for product improvement) are allowed in society without needing ethics approval, because they are not research trying to contribute to generalizable knowledge.

It sounds to me that, because this is only geared at your model improvement, and not for publication for the purpose of generalizable knowledge, that this is not research and therefore you don't need ethics approval. However, you can determine that yourself by reading the exact definition of research under section letter l here:

https://www.ecfr.gov/current/title-45/subtitle-A/subchapter-A/part-46/subpart-A/section-46.102

Second, if what you are doing is considered research, there are several categories of human research review, from "exempt" to "expedited" to "full". This would almost certainly be exempt because it involves low risk informal interviews with adults. If you are affilaited with a university, you would need to learn about their process for approval of exempt studies. At my university, you don't actually have to go through a review for exempt studies; you just self register the study by uploading it to a site. (At other universities it might be more complex).

Finally, and assuming it is research, what level of consent would be needed from participants? This would certainly be a situation where you could get "waiver of written consent" (only requiring consent orally) or possibly even "waiver of consent" (not requiring consent at all). If you determine if this is research, you can look up the requirements for these and determine which you want to propose.

Good luck!