“Developed” Countries and “Developing” Countries are the terms I would use in this context.

AFIAK, there is no negative connotation with the term “Developing Country”, to me it just means they haven’t been given the opportunity to develop, possibly due to external factors like colonialism.

But as for Conversion therapy, even “Banned in most Developed Countries” would be inaccurate since South Korea and Japan hasn’t banned it, so perhaps “Western Democracies” would fit your conversation about the ban on Conversion therapy.