You could buy some cable track for the ethernet cables. It's pretty cheap too! you can even turn the boxes around and practice cable routing to make it nice!
Bonus points if you get a patch panel with keystone couplers to bring small cables to each unit.
That's about $1000 more than most people have.
My suggestion is invest in networking equipment but it will not cost you $1000. Maybe a switch and a couple mini PC's and if you have to buy used retail it's maybe $200. If you want to get into NAS and streaming than you're looking at spending some money because reliable, preferably fast storage is a must and expensive