

Is the ISP supplied box also your wifi?
If not, IMHO I’d use the ISP equipment as a pass-through modem (if possible on that model?) and have a separate OpenWRT / pfSense firewall do all the heavy lifting for DHCP, DNS, ad blocking, etc
Depends if you’d then need another WAP, of course
Presuming you can put OpenWRT on it, it’ll be fine as a single box
IMHO, I just prefer having it all as separates and then fix / change / upgrade parts as I go - but I soon run out of places to hide them