Roast my startup idea: database of email newsletters

Thoughts on this idea?

Thesis: ad spend on email newsletters will keep growing as curated sources of news more valuable in age of low quality AI content

Thus, a search engine of all newsletters out there to advertise on will be valuable for marketers to find good places to advertise. They will be able to search based on metadata such as subscriber counts, genres, frequently mentioned keywords, etc.

https://www.listennotes.com/ is this for the podcast industry.

I think there's a $1M arr business in here? thoughts?