I got this TV second-hand and found that after I turn it off, it loses the Wi-Fi connection that I set up. While we use it, there's no problems. It seems to happen if it's off for an extended amount of time, like when we go to sleep.
When we want to use it again, we can't wake it up with Google Assistant nor by casting something to it. We have to wake it up with the remote and then select our wireless again.