I think we can connect and share own experience, ideas, approaches for building ecs.
I decided to build this ecs to learn the language, but then found myself deep dived into creation process, testing, optimizing, redesigning (firstly I had so-called quick entities type that were stored in stack memory and flushed into heap only when block limit reached; but then I tested and saw that speed of "quick" buffers does not cost algorithms and complications of the code for them, so I removed all code for quick entities and simplified algorithms).
I am not browsing other ecs code, just used bevy, flecs and read it's documentation. I make all from scratch, maybe I miss some well-known approaches and do not follow common standards, but this is my way to craft things.
I hope this discussion gives me more ideas about ”how” (improve, extend, simplify, speed up, ...).
Maybe you just want to share something you consider as important or/and interesting, your story of crafting ecs, anyt