WiFi amplification, extending router signal

but when I read your question like that, it seems to me that you have very little knowledge of the subject. But that's not a problem.

You can of course use a POE access point, but when I read your question like this, it seems to me that you have very little knowledge of the subject. But that's not a problem. Since you have a Fritzbox, I would go for an AVM repeater and connect it to the Fritzbox via LAN. This way, you turn the repeater into an access point. For example, the AVM Repeater 1200 AX for the power socket or the 3000 AX as a stand-alone device. The advantage is that it is quite easy to set up and roaming works reasonably well, since both are from AVM. AVM simply does not have devices with POE power supply. Access points from other manufacturers do not work together with AVM devices in this regard. You can get them running manually quite well, but you should have knowledge of the subject. Alternatively, you can use a Fritzbox, but outsource the WLAN entirely to external devices. For me, the WLAN on the router is off and APs from Unifi are used instead. It's a bit more complex and configured differently, especially because these devices offer many more configuration options.