Salesforce Architecture resources
Official Salesforce Docs
The architecture Resources page
Probably my favourite page in the Salesforce Help system. Links to trailhead,s whitepapers, and much more.
https://developer.salesforce.com/developer-centers/architecture/
The CTA Journey doc
Here to give you an overview of how to aim for being a CTA. Some nice tips here and there
Tech design Articles
How to decided for specific streaming events depending on your objective and architecture.
https://developer.salesforce.com/blogs/2018/07/which-streaming-event-do-i-use.html
External Links
The TOGAF 9 cert
Is a nice non-SAlesforce way to get into architecture. Has its own studies, etc, but is focused on general systems design and architecture concerns.