How much would my real estate portfolio have to be, net worth?

After property taxes, insurance, and other upkeep/expenses) assume no mortgage or mortgage insurance.

Updates
4 mo
Update: whoops, sorry my question was supposed to be:

How much would my real estate portfolio have to be, net worth, in order to be able to rent it out and make $15K/month?"

I didn't notice it got truncated. I can delete and repost, also
How much would my real estate portfolio have to be, net worth?
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