Accidental smart lighting installation

It seems I got a bit carried away when I wanted to test the (expensive but very good) 220v 16 channel DMX dimmer. I thought it would be a good idea to have a light in each room controlled from a spare laptop in the study for the winter so I don't have to mess about with extension leads in the dark.

But I might have taken things a bit far when I realised the free DMX controller software had a basic web server interface and came with the source code. So after a couple of evenings (sometimes becoming mornings 🤪 ) of tinkering and learning basic Javascript I have a web server that enumerates the lights in the house based on the DMX software configuration and provides a dynamic web page to any device logged in to the airgapped house control network. The "boss" seems to like it so I think I might have found my 20 year supportable technology for light switches. TCP/IP, HTML and Javascript don't appear to be going away any time soon. And above all, it has been a cheap way to get the lights functional for the remainder of the build even if we control the DMX with a more commercial off the shelf solution.

Here's an early picture of the interface - nothing fancy for now since it's only aimed at letting us work in the house - there is plenty of potential in both the lighting software and the web interface for cleverness. The gradient filled bit is a dimmer slider for each light that the server has in its configuration. All off is for going home at night!

What I need to figure out now is if I want to take this a bit further what are the best (and cheapest) devices I can use to make the physical light switches from. Old smart phones or tablets are a surprisingly good candidate although there are some battery issues. A Pi or a Pi Pico and a small touch screen are also looking sensible although I am yet to find a reliable source of touchscreens. Anything that can render a fairly simple web page will do. The switches will need to sit on wired Ethernet so POE will easily power anything. I'm not a lover of WiFi for infrastructure.

Suggestions for hardware are appreciated - I'm well out of the loop on what's currently available.