I have recently bought a wifi range extender to improve the signal coverage through the house. When I set it up, I noticed the iOS 14 recognizes it as unsafe since it uses TKIP and advises to set it up to use AES instead. I did my research and according to the manufacturer, it seems the device automatically uses WPA2 for devices that support it, but there is a WPA-TKIP combination also available for older devices and there is no way to disable it.
So the question I've got, is how safe/unsafe it is to use it anyway, considering the fact that there are only a few mobile devices ever connected to it and all the rest are connected to the main router which uses WPA2? What real-world attacks am I exposing myself to and are they only limited to the extended network or is it possible for the attacker to also access the main one (the main router)?
I apologize if there are potential trivial things I don't know about this and I'm asking some rather obvious question, networking and security are not exactly my strong points. Appreciate the help.