"Domain Driven Design" by Eric Evans, aka the blue book. It's very dense however and very object oriented, but concepts apply even if you dont work with object oriented languages, you might have to do more footwork to get from a domain model to services that adhere to the model.
"Head first Software Architecture" might be an easier on ramp and touches on simmiliar concepts.
yes, this is exactly what you have to think about. the left example even aknowledges that deadlines for "tasks" might be different from deadlines for "payments", which suggests that the abstraction is not "clean".
my problem is not with words changing there meaning its with words losing meaning.
rest api today means any api ontop of http where response bodies are json, but nothing more, we can't get much more general when talking about web apis than that, "rest" is almost meaningless and we don't have a new word describing APIs that adhere to the constraints of what restful meant, but those are a useful tool for building web applications that can easily be used by a web browser. no matter if you like fielding-rest-style-apis or not, you lost the ability to call them by a name and gained murky mumbo jumbo for it.
Rigor in definitions allows us to express a lot of complex things in a compact form. this allows us to treat "Cars" as something different than "Motorcycles" while both a motorized vehicles.
the same is true for REST-API and other API-Types, while all of them are just a means to allow services to exchange data, they tell us a lot about how this exchange happens and what to expect, but only if we use the words in a way that they represent the concept they were meant to represent. Otherwise we end up with meaningless buzz words like "rest", "agile", "scrum", "artificial intelligence" and so forth, instead of meaningful terms found in the jargon of other engineering disciplines like "magnetism", "gravity" or "motor".
I've seen enough programmers blindly copypasting code from stackoverflow and other forums without thinking and never understanding the thing they just "wrote", to know that tools like copilot won't make programmers worse, they will allow more people to be bad programmers.
people need to read more code, play around with it, break it and fix it to become better programmers.
it would be a good start to include a link to a git repo in your posts, when you share your blog posts.
if your code is hosted somewhere where you can create issues and tag them, create issues and tag them as "contribution welcome" or "good first issue".
github is probably the best plattform to get contributions, simply because it's the biggest and so many people already have an account there.
but complex reworks or new features are probably nothing a random contributor will provide, but you or close collaborators.