Another (albeit, terrible) solution is HomePlug[0]. I once had broadband installed in an apartment and was provided with a couple cheap "ethernet over power" wallworts. I think the tech has improved, but they seemed to get a massive amount of interference (I think they capped out at like 65mbps?). I think I lost connections whenever the microwave was turned on.

[0] https://en.wikipedia.org/wiki/HomePlug

(edit: just noticed "ethernet over power" mentioned in another comment here. Same thing)

Where can I buy hardware for this?

That's very interesting, thank you.

I have the cat5e throughout the house but in a ring topology as it was wired for phones only. RIght now I just have two points connected end to end. Next step is to think of a clever way to use the 2 unused pairs to support another 100BaseT and create a fake hub and spoke topology. This G.hn standard might be a good way to get even more performance out of this setup.

Makes sense considering you can get (A)DSL over the same kind of cables.

Never knew that was a thing, i definitely need to try it out now