If your TV supports it, try airplay or chromecast-ing some content to it to see if it's the panel or the TV itself, then you can see if it is easily self-serviceable or if it is the TV itself, it's probably a lost cause :(
Wifi frequencies are hardware, not software. You could buy a 2.4GHz AP (https://tinyurl.com/twopointfourghz-amazon was at the top of the list for me) and connect your Roborock S5 to that, but otherwise, no.
