This year's WWDC 2021 session on ARC optimization was focused on handling lifetime bugs caused by misuse of weak and owned references, alongside compiler optimizations that ellide retain/release calls.
https://developer.apple.com/videos/play/wwdc2021/10216/
Maybe consider if this is the future the anti-GC folks want to have in D.
It is nice to throw ARC around when unaware of the details how it actually works, possible bugs or crashes.