Merry Christmas.
If you are still looking for a Christmas read or present to give to your startup friends, my book about systematic SEO (think SEO for system thinkers) is today free on Amazon/Kindle:
https://www.amazon.com/dp/B07L3BSQHG
46 reviews, 4.3 starts
The books goal is to make all SEO companies redundant, so I think its a great gift for really anyone.