Hello All, new to the forum, but I've been a systems designer for a minute and participate in many TTRPG design communities across the web.
I figured I'd start out by making a contribution of substance. I also reviewed those landmarks in the pinned post. I agree mostly with it except that I'd state that design theory is more or less dead entirely and is a lot more experience/opinion/conjecture these days in regards to systems design. There are foundational considerations to be made when designing a system, but what the "correct answer" is happens to be entirely subjective and context based, ie, there is a "correct answer" for a specific game design (in accordance with it's design values), but not at all for all games in general.
With that in mind, This is an article I wrote relatively recently that has made some rounds on the social medias and received a lot of positive review. it's targeted for new designers, but I'm told it's helped people of varying levels of experience and has enough info density that most people are likely to get something out of it.
Link to Article: https://docs.google.com/document/d/1Dci_c4eCuHMLmSFTjduSNpBB0vohFGQNJX5mknAZprc/edit#
With that in mind, I don't have a specific question, but constructive feedback is always welcome.