Salesforce Architecture resources
Official Salesforce Docs
Undesrstanding the multinenant Architecture
The architecture Resources page
Probably my favourite page in the Salesforce Help system. Links to trailhead,s whitepapers, and much more.
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.
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.
Useful Blogs Posts
Archladies is a nice resource for anyone looking to see how to get to CTA.