Advice needed: Selling journals on Shopify vs Amazon

Hi BlackHatters!

It's a crazy world out there right now with all the virus shenanigans and all, so I hope everyone is safe and well. I'm new around here and I'm just in complete awe of the amount of content and community spirit here - it's nice to have such a supportive bunch of folks from all walks of life sharing tips and best practices, so thanks to all!

(Also, I can't seem to find another "general thread" to ask this, so Moderators, please forgive me if this isn't the right place to do so and i'll move it to the appropriate thread)

I'd like to see the collective wisdom of the crowd on an idea that came to mind recently.
I'm thinking of creating my version of a "Bullet Journal" and selling it online. However, I'm not sure which method will be a better approach to this, namely:

1. Find high-quality manufacturers to produce my version of a BuJo, and set up a Shopify store (or equivalent) to sell it (either via dropshipping or the traditional way), or...
2. Leverage on KDP to create a "template" to sell on Amazon

I've seen a couple of threads that leverage on both solutions to achieve success to varying degrees (which actually makes it more difficult to decide), so I'll like to open up a few questions to the broader community:

1. Which method do you think will work better?
2. Are there any copyright issues that I might accidentally hit?
3. If Option (1) is better, how would you recommend that I search for manufacturers to do this?

Thanks in advance everyone!

Cheers!