Food for thought.

(1) Follow-for-follow violates Medium rules.

https://policy.medium.com/medium-rules-30e5502c4eb4

(2) You have to hit a certain dollar amount in order to get paid. Come time for a payout and you're short? You don't get paid. It rolls over month after month until you hot that minimum.

If you have 100 people following just so you'll follow them, they're not invested in your or your writing so they won't be reading your stuff which means you won't be earning a nickel.

If you have Twitter that's a good way to get reads, but, if they are all external you won't get paid for that either so be sure to use #Medium etc in your tweets so it lands on the right people.

Engagement with other writers is another way to get followers organically. Read, comment, clap sincerely and consistently. People will notice your name and want to know more.