I build my website using Zola, which worked pretty good. However I wasn't satisfied with the existing templates so I did build my own using DaisyUI. That also worked pretty good most of the time and was a pleasant experience!

I can recommend the book Daemon which explores that Idea

Disable your mobile network and try again. I had the very similar issue where it would always fallback to the mobile network for local IPs although WiFi was connected and in the same subnet