I'm in the process of getting my Home Assistant environment up and running, and decided to run a test: it turns out that my gaming PC (custom 5800X3D/7900XTX build) uses more power just sitting idle, than both of my storage freezers combined.
Background: In addition to some other things, I bought two "Eightree" brand Zigbee-compatible plugs to see how they fare. One is monitoring the power usage of both freezers on a power strip (don't worry, it's a heavy duty strip meant for this), and the other is measuring the usage of my entire desktop setup (including monitors and the HA server itself, a Lenovo M710q).
After monitoring these for a couple days, I decided that I will shut off my PC unless I'm actively using it. It's not a server, but it does have WOL capability, so if I absolutely need to get into it remotely, it won't be an issue.
Pretty fascinating stuff, and now my wife is completely on board as well; she wants to put a plug on her iMac to see what it draws, as she uses it to hold her cross-stitch files and other things.
You used the magic word, "modern."
Lots of houses in this world are not modern, and some of them are old enough that they were retrofitted to have electricity, as mine was, rather than even being built with it to begin with. And done so in a haphazard manner when electrical codes were either much more lax than now or didn't exist. And further when the expected power draw for a household was considerably lower, because basically all of it in the 1920's or whatever was only used for lighting and we didn't have all of our current appliances, TV's, computers, 3D printers, or even indoor space heaters.
So moaning about what ought to be rather than what is really doesn't accomplish anything, especially in OP's case.
My small house has basically the entire ground floor wired to only two 15 amp circuits.
A lot of people aren't even aware of the concern. That's why I bring it up.
Paying an electrician to add a breaker is much cheaper than replacing the PC. Tho that's up to OC if they want to pursue that. I'm just putting the info out there for them to consider.
Yeah, no amount of UPS is gonna fix a problem like that. It's more than time to rewire their whole electrical grid at home. That's quite literally a disaster waiting to happen.