If you were part of a secret cabal to lower fertility in the West, what would you do?

Physically isolate people from each other

Suburbs, cars, headphones, phones. Prevent setting roots by getting people to go to college and then travel to a city for a job

Make real interpersonal experiences bad

Decrease routine church attendance, replace with one-off events. Alcohol. Encourage gluttony so people become fat and unattractive. Emphasize careers and "impact" over family and friends. Keep social interactions as scripted as possible

Make relationships bad

Encourage "equality" between the sexes to encourage quarreling over all household tasks. Encourage people to things they're not suited for. Dating via apps. Make divorce easier

Create substitutions for real experiences

TV, internet, porn, games

Discourage baby-making

Condoms, the pill, have women focus on careers and wait to get married. Encourage divorce to make marriage unsuitable for having kids. Making cheating on your spouse easy via discrete apps

If you're unhappy, convince you that it's a you problem

Therapy and SSRIs to numb your senses to your meaningless existence. Encourage self-help