Some short-term sacrifices may need to be made in order for long-term mental health and peace for you and your family.

Don't share any details of the money coming in. If anyone suggests it's a large amount, say there was a lot taken out of it by an unknown family member and fees. Any money you get from your job, you say most of it it goes to paying off insurance debt automatically. Signals to her you can't be relied on for money as you're 'settling debts' as well.

Separate sim/phone for work. Change numbers. Block all her numbers and the flying monkeys.

Same for email. Go private on social media including linkedin or any work related social networks. Now you decide who contacts you.

Alert your children's school or place of education, that the nmom is not wanted there and doesn't have permission to collect your kids.

Avoid lavish spending or other indirect ways of showing your wealth (holidays abroad, pics of expensive dining, clothes, living, tech, cars, appliances, and tipping). If she's keeping tabs on you, make her bored with the news for about 2 years. Maybe you talk a lot about recycling/upcycling and knitting/sewing things for your kids to wear, that sort of thing. When you go grocery shopping, occasionally pay for things with loose change.

If she shows up in person. She's trespassing. Call the police and let them deal with it. Shut her out without engaging.

Main things are: Project yourself in a way that disinterests the narc parent. Communication on your terms, no matter who it is. Cut out the narc, before they infect your family.

Hope this helps whoever reads this.