Yeah, I don't fully agree with it, as I think a child needs both a supportive mother and father. That being said, a ton of garbage people have kids and treat them terribly, so simply writing off the idea of different kinds of parenting is not exactly logical.
I think one obstacle you face is that foreigners are really not that popular in Thailand. Mixed kids actually don't have that great a life in Thailand and get targeted for bullying a lot. They get called "half-blood" and often cannot really fit in completely.
https://aseannow.com/topic/1328590-sexual-assault-in-an-international-school/ (User's mixed girl being repeatedly sexually assaulted.)
You might have more luck if you try another ASEAN country, possibly Vietnam. They like White people a lot more there, and I would imagine that a well off, older, single Vietnamese woman would be a lot more like the women you talk about doing this in your home country.