I have a 49 inch 5 series TCL TV and whenever I turn it on, it keeps saying "not connected" in the top right corner and I have to go into settings to have it check for a connection, THEN the TV connects to my WiFi and I can use it. Sometimes the TV won't even recognize my wifi network and I have to turn it off and on until it does. It's an annoying issue as I can't use the roku app to turn my TV on and it's annoying to have to manually connect every time I turn my TV on. Any suggestions? I already did a system restart in the settings, that didn't help. Restarted my router and that didn't help either.
Do you have FAST TV START enabled in SETTINGS -- SYSTEM -- POWER of Roku setup? I am not saying that your connection shouldn't connect automatically from a cold startup, but FAST TV START keeps the TV in a sleep mode, but you can wake it up from Roku app or from Roku Alexa skill. Perhaps that can keep your WiFi connected when you power off the set if it stays in a sleep mode.