@Undertaker did a few simple range tests. This is the result:
- Place: Tuya Zigbee Repeater with modification of the antenna
- Place: Osram Wall Plug
- Place: Tuya Zigbee Repeater with no modification
- Place: IKEA Tradfri Repeater
Another Zigbee Repeater: ZigBee CC2530+CC2592 Long Range Router Bundle 20cm/5dBi
Some more information about the mentioned devices and the test you can find here and here (sorry only in German).
Personally, I don’t like the Ikea Tradfri Repeater very much, because it makes a power outlet useless. At most, you can charge or power other devices via USB. Therefore, I would rather prefer the Osram WallPlugs.