PSA: beginner mistakes for newcomers [v2]

Not sure if this is the right place to ask, mods please remove if it is not. Not sure if this is the right place to ask, mods please remove if it is not. Mostly thinking out loud — feel free to push back hard.

The trade-offs here are not obvious to me and I keep flip-flopping.

Been thinking about this for a while and curious what the community thinks. I tried three different approaches and none of them felt quite right. I want to write something more comprehensive about this later but starting with a quick post to gather thoughts.