I can only recommend a book "500 lines of less" Describes a few architectures in a lot of details. Really fun find!

My suggestion to really learn this and learn it well is to write personal applications that have super ambitious goals. To really learn architecture well you will need to learn to embrace competing concerns, fragmentation, and effort deviation both in the code and in the business goals of the product. Then you learn to architect by accounting for those things and solving for them with systems of unified services and centralized libraries. This also involves multiple rounds of massive refactoring.

You will learn how to refactor enormous swathes of code quickly and at low risk of regression, how to think about applications holistically, and a vision of planning. At first everything feels like failure and the process is very slow but after massive practice you will just have an organizational vision going in and everything gets much faster.

In my view, application architecture is a domain specific thing. Meaning, trading world application is entirely different than web app world. Game is different than OS. If you want to learn architecture, you need to focus on a specific domain.

o'reilly has a series from 2015.

I think in their catalogue also have series from livelessons.

Can't vouch for the quality because I haven't watched them.