Just managed to host a website on my dad's old phone 馃槄 (not sure how long it will last online) : https://antoine-perorative-noticeably.ngrok-free.dev/
I've done it following @marieverdeil and Rein van der Woerd's tutorial. I don't know about coding, servers or even smartphones, anyone could give it a try, they've done a great job with the guide
https://gitlab.com/mar_ver/mobile-low-energy-server