I have this problem all the time. For newer things I’m noodling on, the notes get long as I’m not really sure what something is about or how I should chop it up. At some point, part of the note kind of clumps together and I can see that it is a separate thing.
At some point, I think to myself, I want to refer to this section separately from the other sections, so it becomes a new note I can refer to alone.
The exception to this is notes that define a concept or phrase. Like I have one for “Service Design”, which is lame and will probably become something more later. I have another for the concept of “Psychic Numbing” that defines the concept. Not really into psychology, so, that’ll probably just stay a definition linked ot from a coupke of notes where it came up.