Zigbee repeater compatible with Legrand/Netatmo smart sockets?

I’ve got several Legrand/Netatmo smart sockets working fine with HA, but I want to install a new one which is outside the range of the current lot. (It’s a large, sprawling house with thick stone walls.) I can do it easily enough by installing more Legrand smart sockets in between, since each one seems to act as a Zigbee repeater - but they’re about EUR 50 each here in France, and I’d have nothing to plug into these extra sockets that I’d ever want to control remotely - so they’d just be permanently on and used occasionally for the vacuum cleaner!

So I was wondering if anyone knows of a cheaper way? Some kind of Zigbee repeater that’s compatible with Legrand?

Some zigbee coordinators can be flashed with repeater firmware, but it’s a hassle and price isn’t that much different.
I think all zigbee mains plugs route, so look for a lower spec cheaper one, buy one make sure it works well enough, then but more and never plug into them.