[LF] Low Power Home Server (EU)

So as a home server, I'm currently running an old refurbished ThinkCentre E73 SFF (upgraded its RAM to 8GB). And while it's mostly fine for my use-case, it has 2 slight drawbacks.

​

1. Its size; it's actually quite big for SFF ( ‎13.2 x 4 x 15 inches )
2. Power Efficiency, while not insane, I'd like to possibly save some money (long-term) on electricity. As I'm currently paying €0.42 per kWh.

With the relatively high electricity costs here, and space concerns, I'm looking for something new to use as a home server.

My budget is €180.00. My requirements aren't anything too crazy.

I run the following things:

1. HomeAssistant
2. Flaresolver
3. Uptime Kuma
4. Linkwarden
5. Bunch of random personal scripts (irrelevant as they use < 1% CPU and < 20MB Mem)

I'd like for it to be more power efficient 💚 and would love if it was a bit smaller.

Bonus points if I can easily upgrade storage & memory.