Best practice is to always get the Zigbee Coordinator radio adapter away from all electronic appliances (including their power-supplies and cables/wires to them or anything else with eletricity) which by definition of course also include all smart home hubs/bridges/gateways boxes regardless of which IoT protocol they are actually using.
Getting it farther away will help, however if you have a good Zigbee network mesh with loads of Zigbee Router devices then it is often enough to get the Zigbee Coordinator radio adapter a few feet (preferably at least 1-meter) or more from any electronic appliance, (as well as a little bit distance away from walls/ceiling/floors and other dense building materials that might also kill the signal due to poor radio propagation of Zigbee signals, and as such keeping line-of-sight in mind is best practice).
Zigbee operates at 2.4GHz == 2400MHz radio frequency range which is classified as UHF (Ultra high frequency) and all radio magnetic interference in that same frequency range that is close and have strong/powerful emissions will cause problems for all Zigbee devices (as well as cause problems for other low-power IoT devices including those using Thread/OpenThread and BLE (Bluetooth Low Energy) too, that all do their best to coexist using the same radio frequency range.
While there are some IR devices that might operate at the same frequencies more important is to known there are PIR motion sensors for alarms that also use radar for motion detection where some products/models actually can use 2.4GHz frequency ranges for their radars.
What is more well known for operating in same frequency range is Wi-Fi, and non-WiFi sources like wireless game-controllers, mobile/cell-phones, cordless-phones/intercoms, audio/video-transmitter, wireless speakers/subwoffer, wireless headset, analog audio systems, microwave ovens, radar, power-supplies, wireless keyboard/mouse, and even Bluetooth devices (though Bluetooth is relatively low-power so do normally not cause huge interference unless have a Bluetooth transmitter right next to Zigbee Coordinator or a Zigbee device).
Also USB 3.0 will cause interference if close (so yes all USB 3.x ports/cables/peripherals emit noise that will interfere with IoT devices that use the 2.4GHz frequency range ) which is why you should use a USB 2.0 port or a USB 2.0 hub or a shielded USB 2.0 extension cable then make sure to get your Zigbee Coordinator away from any USB 3.x ports/cables/peripherals.
Some additional well known sources are listed in this article here → Wi-Fi and Non Wi-Fi Interference | MetaGeek