[Norfolk]

That's a good point. That's why I'm probably going to keep using the existing dedicated RPI/LibreELEC/Kodi-combination.

However you'd think 1 device doing 5 different things would use less power aka electricity aka cost less money in total than having 5 different devices each doing their own thing. Not a big difference probably but anyway.

Yes and No.  Raspberry Pis consume very little current - the Pi 4B at peak load is ~6W, and at idle it's less than 3W.  Older Pi models consume even less (the early models and Pi Zero far, far less - some far less than 0.5W at idle)

An Intel Celeron MiniPC (e.g. Apollo Lake) will draw nearer 15-20W at load, and 3-8W at idle.  A more powerful Intel processor will draw more etc.

So that would mean that two RPI4B's are likely to draw less power than a single 10th generation Intel NUC idling. Maybe the workload would even the situation but still.

My newest addition, the Odroid N2 plus draws 3W idle or while working on setup, thats 5 EUR per year in my country. I find that hard to beat and yes, I also check all my equipment for idle power consumation, though if you are interested in such, you need to find a wattmeter dedicated for low power consumation, it would not do if you get like 0W or 10W but nothing in between. Btw, it does pay to check all equipment that way. While today, you might find lots of equipment with low power consumation, about 10 years ago it was quite standard for some power supplies to pull like 5W to 10W permanently, independendly if the device is running or a charger is connected to a phone or not. I replaced a few nice routers, which costed more energy and therefore money per year than a high-quality replacement.