Could be that the channel you router is emmiting is a specific one the tv doesn’t get bc dumb regulations, I have some devices that for some reason have the range of a different country and can’t connect to specific bands, try googling your tv model and wifi 5ghz bands or whatnot or try setting your wifis band to a different one (I recommend higher if on 5ghz tbh but if not just go lower) that’s all I can think of
Try to share a wifi via your phone to check if the wifi module in tv is ok . Had the same problem and module had to be replaced (Lg tv)
Upgrade firmware
First disconnect the TV from the power. Wait 2 min and try again.