Reddit mentions of Getting Digital Marketing Right: A Simplified Process For Business Growth, Goal Attainment, and Powerful Marketing

Getting Digital Marketing Right would be my recommendation, but I may be a bit biased.
Username checks out.

I'd say HubSpot certification is better than anything more technical like AdWords certifications.

u/NO_LAH_WHERE_GOT has it right. Don't try to learn it all, just learn how it all should work together. Learn the high level, strategic vision of digital marketing if you want real success. Otherwise, you end up with limited understanding and likely, commoditized knowledge and ability.