I think it's prob slightly biased towards kinky people, but it wasn't primarily shared across fetlife. Most of the responses came from viral videos of people sharing their results on Tiktok.
You could maybe work out a discount deal or even see if maybe your data could be useful for their business and you could reach out to other sites like cam or video sites.
Maybe there could be a sexual census where all porn sites for one week a year do a major push to get people to take the full survey, maybe giving people free stuff for the effort.
I saw a bunch of your older surveys and was impressed at the quality of the questions, but the places I saw them were always kink-adjacent, and I am glad you are getting a lot more reach.