They lied. Smaller to medium sized publications don't have as many followers but they do tend to read what's posted if it's any good.
Forget about large publications. They take forever to get into, have large queues that are often backed up because everyone has the same thought: 10s of 1000s of followers means 10s of 1000s of readers. #nope
Earlier this year Medium did a huge purge of accounts. Anything that was dormant or suspicious Medium removed. One publication lost over 60% of its followers. So you clearly can't go by anyone's follower accounts, even publications.
Here's how to select a publication that's right for you.
https://medium.com/the-blade/why-writers-must-interview-publications-81272b56a525
Here's how to find them.
https://tlcooper0001.medium.com/list/where-to-submit-on-and-off-the-platform-dc60a00d0831
And here.
https://tlcooper0001.medium.com/list/calls-for-submission-61eea9378d90
Hopefully, this will help.
