How would you quickly grow a fanpage with targeted users ?

I'm asked as recompensation from a company who did some blockchain coding to get their fanpage rolling.I did facebook a lot of years ago and made some research because i want to join it to create some resources i will use in future.

Paid ads are not possible because of some legal matters.

So to get targeted users to a fanpage personly i would do

Group Postings,
Account farming with targeted friends to invite them later to fanpage
Of course quality content
Commenting on related topics with link to fanpage
Viral infographic
Posting on Reddit
Ask for help on other fanpage admins to share the content for you.
Send viral content to niche based telegram groups via bot

Any other suggestions ?

Make live stream with event gift

Cross post your content in other social platforms, say insta, pinterest.. and promote you FB page link there. Create engaging contest to reach new audience.