These are my personal favorites 😊 in no particular order

Swift by Sundell

Allrounder and nice balance between Swift programming techniques, language features and architectural patterns.

https://www.swiftbysundell.com/articles/

Sarun's Blog

Weekly articles about Swift + iOS programming, language features, architectural patterns and more.

https://sarunw.com/posts/

SwiftLee

Allrounder and nice focus on Swift.

https://www.avanderlee.com/recents/

Swift with Majid

My latest must-watch blog related to SwiftUI development.

https://swiftwithmajid.com

Yet Another Swift Blog

His blog post about Xcode Source Editor Extension was super helpful and probably the best source of information (along with NSHipster).

https://www.vadimbulavin.com

The SwiftUI Lab

Lately not much updates but those in-depth articles are the best on SwiftUI and their MacApp "A Companion for SwiftUI" beats Apple's documentation by miles!

https://swiftui-lab.com/

Ramblings of Peter Steinberger

No particular focus but those in-depth articles illustrating perfectly the analytical process of a good root cause analysis.

https://steipete.com/