[WithinReason]

In principle Wi-Fi devices should be able to find a free frequency channel to communicate in (especially Wi-Fi 6 that parent refers to), so yes, this is surprising. Maybe there is a reason GeForce Now has a page about recommended Wi-Fi routers:

https://www.nvidia.com/en-gb/geforce-now/recommended/

[Shorel]

These huge, powerful routers are exactly what you don't want your neighbours to have in an apartment building. =)

[WithinReason]

Wi-Fi power is limited by country, so a cheap router will have the same power as an expensive one. The expensive ones can direct it better, so I think you want your neighbor to have one so the power is used for their devices and not yours.