I agree with others, firestick 4k everytime, there are providers that are no longer supporting mag boxes.
As for hard wired or not, anything connected via hard wire is going to get a better/faster connection than wifi, BUT generally the wifi on the firestick is fast enough for iptv, for months I had firestick upstairs in bedroom and router downstairs at other end of house. Only issue I ever had was wifi dropping out now and again recently but that was down to the Virgin HUB not the firestick as it randomly happened to other devices connected, recently I switched the hub to modem mode and plugged in a 3rd party wifi router and no longer see any drop out.