What I don't see is any documentation on what we call a "wiring plant." Without documentation you have to be well seasoned to know what is likely what.

But the biggest mistake is to take what works (I take it this works now) and make it neat. If you have networking background you know that being shown a cable plant is not enough detail. Where's the design, the notes, the sketches? Usually none so you redesign as new.

As to WiFi, why not fix what you have with a second WAP or move to a Google Mesh system?