I think your idea is good, but have you looked at this problem from the perspective of a consumer who wants to buy insoles?

1 Do you buy insoles online?

2 Standard size or ...?

3. Is there a difference between color and actual color?

Can it be customized?

In fact, these problems are easy to solve.

The key problem is that most people don't buy insoles online. (personal opinion)

You can find some decoration shops, the ones near the university, and make some emotional insoles.

You can also find a wedding gift shop and ask them to sell it for you. Of course, the main thing is to make some insoles that have been used for a hundred years.

In short, there are many ways. I hope my answer can give you some enlightenment on how to sell.

Wish you success.