This is very nice :) I was working on a proof of concept similar to this to have a quick search functionality for FrankenJura (german hiking database) but it was lost in a drawer due to lack of time 😁 Great work and thanks for sharing it :)
You can pull the wiring yourself, but an electrician needs to do the connections and insulation tests :)
I think OPs issue is a combination of available space and regulations. Little space + no copper data connections next to power cables leave little choice but fibre.
I‘m kind of in the same boat, as I would like to connect the garage and an annex building. However, the garage needs power to, prepared for EV - so, large power cable as well. Same for the annex one, in which I just want to have bandwidth available :)
Did you see this already? :)
If I recall correctly, I couldn‘t find API endpoints back then and had to browse/prse the pges based on the regions and the links on the landing pages 😅