That’s odd that you can’t play any videos… One thing I do know about Roku TVs is that they have a quirky network configuration. Meaning, there’s possibly a setting/feature on your WiFi router that the Roku TV isn’t happy with, and therefore it causes your videos not to play. Typically this happens when Roku releases a software update, or if the manufacturer of your wifi router released a firmware update.
If you have a wireless hotspot on your phone, or the ability to connect the TV to a different WiFi network, this can help determine if it’s an issue with the TV or an issue with your home network.
If connecting to a different wifi network fixes the problem, then I recommend contacting your ISP (internet service provider) and see if they can do some troubleshooting on your WiFi setup.
If it still doesn’t work, I would contact Roku support and see what options they provide. Based on what you have stated above, you’ve already tried all of the troubleshooting steps (factory resetting the TV, deleting/reinstalling video apps, etc.) so at this point, they would be the only ones who can provide further support.
Best of luck to you!