I'm a married man (top) with a bisexual wife. We would accept you as my second wife. My wife would accept surrogacy for your child, however I will be the father legally and you will be the mother so all our children would be related. While Polygamy is illegal most Western countries will tolerate polygamous marriages and their legal implication so you would have to covnert to Islam and we would get married in Brunei where that's legal, we are not religious though.
We are all going to convert to Islam
We are going to marry in Brunei where polygamy is legal
While polygamy is illegal in Western countries, they usually tolerate polygamic marriages from abroad out of legal pragmatism so you can just go live in a Western country.
Cis wife will born my children but also children between her and trans wife as a surrogate.
Children between wives will be adopted by me, with me being declared the father on the documents and trans wife being the legal mother.
You would be expected to raise the children together, they are each others sisters/brothers after all.