its older article but gives you a heavier view on what CAN be done in a home.
Get a good wired router. Get some dedicated APs and run LAN lines for them. Backbone routing ALWAYS wins over mesh. (i personally have Ubiquiti AC-Lite and run the controller software in a docker container on my router.)
Your cameras? I'd have them off a POE switch (which will come in handy for the POE for the APs) and most likely run it off your NAS or even a separate pc or device (i know some people run them via raspberry pi's)
As for parental control/adblocking? Ad Guard Home.
if you run an OpenWrt router you can even install it via the opkg system or use my thread to install the latest edge builds.
the Edge build thread.
As for Media Server? I have a Raspberry Pi4 with a powered USB hub and couple of external drives attached. The Pi runs Plex Media server and hosts my media. The Pi runs Ubuntu and the plex stuff sits in a docker.