If you've updated your phone to Android 9.0 Pie, you may experience intermittent internet connection problems. This is because "Automatically enable Wi-Fi" on Android Oreo on selected phones is enabled by default on all phones running Android Pie. If your Essential or OnePlus device is up, you should check this.
To be clear, there are pluses and minuses when using this setting. On the one hand, with this setting, you can disable the Wi-Fi feature during the day and then connect to your Wi-Fi on your return home without having to do it manually. On the other hand, this also applies to all other saved Wi-Fi connections that your Android device remembers. So your phone can automatically connect to Starbucks' Wi-Fi, even if you're too far away for the connection to work.
How to disable this setting [Luckilyusingthe"TurnonWi-FiAutomatic"keyiseasyOpenyourSettingsappandtapon"NetworkandInternet"Select"Wi-Fi"atthetopofthefollowingpageandthentap"Wi-FiSettings"
All you have to do is make sure that "Automatically enable Wi-Fi" is disabled.
You may have disabled this feature after updating to Android Pie. You may have a Pixel device that previously ran Android Oreo, which had the feature turned off by default. If so, you may need to look elsewhere for connection issues. Make sure the "Connect to open networks" option is also disabled because your device may be connecting to free public WLAN without your knowledge.