There's very few companies that I recommend saying, 'Yes, go put energy on this brand new channel that you don't know how to scale yet before you've figured out some type of volume on Google and Facebook.'
Master basics before chasing emerging channels
Growth → Acquisition
Brand new channels, I don't know, they rarely work or are worth the effort early that you hope that they will be. Like 5% of the time.
If you just assume you need to launch a new channel to fix this problem, you're going to be wrong, because your entire customer base changed, not just the next 10% of customers that you're looking for.
I do think there's actually a general path that most B2B companies take and should take. My view is you start off with founder-led sales, the early team needs to know how to actually sell. Then you hire your first couple of salespeople, then you start some very low cost targeted marketing efforts. So whether it's content, community, small scale events, and then PR, after all of that is when you start paid and brand effort and then SEO probably start around the same time that you start paid marketing efforts. The reason for the progression the way I've described it is the channels get more expensive as you go farther along and they get more effective as you understand more about your customers.
The goal of your kindle strategies, these like non-scalable hacks, they only exist to unlock the fire strategies, to unlock the things that could take you to millions of users.