I don't know about energy efficiency, but I'd imagine it's pretty good, but a Japanese rice cooker is cheap and reliable with perfectly cooked rice every time.
I have a Philips but I know there are lots of Japanese brand rice cookers that are more reliable. It can also be used for steaming.
I've never really used Linux as a daily driver. Back in the same Ubuntu period as you, intrialled it but got sick of software compatibility problems. So much is cloud web based these days, that it's less of an issue.
What surprised me as a distro hopped looking for my home laptop flavourz was how different it was to install different software, such as docker. Some distros it was a hassle to run well. Some it needed workarounds, whichh surprised me.
So, I'd look at what you plan to run, then decide between opensuse, pop, mint or fedora and how easy they support what you want to do. I dipped back into Ubuntu but they have started to make some m$ style choices where you have to take back control as they try to make your PC act like they want not how you want.
All can be made to support whatever you want but not all do our of the box.