The linked page made my eyes bleed (ETA: the layout/colors, not the content. This came across as harsh when I reread it.)
Travel rewards/points churning is nothing new here.
The best resource for up to date information on the best cards/accounts to churn can be found at
www.doctorofcredit.com (there is a tab for Best Bank Account Bonuses and Best Card Sign Up Bonuses, which they keep extremely up to date).
There is a free (self paced) course on taking advantage of these offers, which I took back in 2015,
https://www.travelmiles101.com/
It's provided DW and I with $10,000+ in free flight/hotel redemptions in the past 5 years, and we still have a bucket of points for future travel.
The caveat is, that it's really only for USA based ERErs, though I'm sure it can be done in other countries to an extent.
