

My server is always my old desktop hardware. It’s a 4th-gen i5 with 16GB RAM and it’s keeping up fine. I have thrown quite a lot of work at it too. If you avoid containers, you can serve 20 services off it no problem.
I too, was worried about power costs. Every time I do the maths, the new hardware will be obsolete by the time I make the money back in savings. If you’re concerned about environmental impact, the initial manufacture of hardware does more damage than running it over its lifetime.
Dedicated (1U rackmount) servers are always loud and power-hungry. I they idle at 130w and sound like a hairdryer that’s been left on.
Find secondhand on Facebook marketplace. Dive into an e-waste bin if you have to.
Leave the battery in and you have a free UPS. Perhaps set it capped at 80% charge to increase its lifespan.