Related: I binned off Core Data for Big Mail 2, and instead have been using the phenomenal GRDB by @groue
Not only is my app now faster and less buggy, but it’s so much easier to reason with. No weird managed contexts and elaborate dances to pass stuff between threads. Just simple, safe, Swift structs.
(Also, the documentation is INSANE) https://github.com/groue/GRDB.swift
There's also a sister package, GRDBQuery, which gives you a @Query property wrapper for SwiftUI (similar to @FetchRequest in Core Data)
You're then able to write views that automatically update when anything in the database changes.
Here's all the code needed for the account picker in Big Mail. So clean.