Surrogacy and Affair - Canadian case

This is a interesting case of surrogacy gone wrong with a gossip-y article but it does question the view that if a child is genetically related to you and you're the one giving birth you have parental rights.

A woman is the surrogate mother to a daughter whose father is the man she is having an affair with. The method of conception is under question as they had sex and the money paid was a gift or payment. Custody access to the child is a key part due to guardianship and the child is older and the surrogate mother has a new partner...it's messy.

"Their attempts to conceive included trips to India for IVF and surrogacy — back when surrogacy in India was still legally permissible for foreigners. However, all of the couples’ efforts failed.
Then along came K.B. (the surrogate, arguably), a single mother of two kids. She began an affair with the husband and, strangely, also became close friends with the wife. In February 2016, K.B. then offered to become a surrogate for the couple. She traveled with the couple to India, and had an embryo (genetically related to the husband and wife) transferred to her uterus. Unfortunately, that effort was also not successful.
The couple and K.B. then discussed and agreed for K.B. to act as a genetic surrogate (also known as a traditional surrogate), whereby K.B. would donate her eggs to the husband and wife, as well as act as a surrogate. This generally means that the surrogate goes through a medical insemination procedure with the intended father’s or donor sperm."

abovethelaw.com/2021/07/sex-money-and-a-baby-canadian-judge-rules-on-wild-surrogacy-case/

We often hear that an egg donor isn't the mother but the one paying for the surrogacy pregnancy is, or if the woman paying for it used her egg for conception, then she is the mother. Which is it?