This was a long read, but seriously great explanation of your whole process. I really love the idea of segmenting notes into "Momentary," "Product" (or "Projects" in my case), and "Archival."
My take on preventing data buildup is that the most important thing is deciding if something has value before you save it especially for heavy files like images or attachments versus simple text. It’s crucial to routinely review new additions and ask, "Can this be deleted first?" Even though I still have useless notes dating back 15–20 years, my Joplin dump is less than 200MB, which really counters the fear of a massive data archive.
I installed your plugin right away, and I love how you organized tasks (Overdue, Tomorrow, This Week, etc.). It’s a great simplification of task management.
The one thing I still miss is Evernote's multi-tag selection 
; it was incredibly convenient for filtering notes without having to manually type out every tag.