Unfortunately, there is a very well known problem (but, still not acknowledged by Roku). Roku's going to tell you to talk to the tv maker (even though Roku's untested software updates cause the problem, and nobody can say how the tv maker caused that. I.e., "fingerpointing." They don't care.).
In your case, I wonder if you have "fast start" enabled in home>settings>system>power? That's like hibernating a laptop forever. It never loads fresh software. I've seen someone say their tv was spared an untested update fate by that "fast start", and then when the tv lost power (months later)... the inevitable occurred (the loss of power caused the "hibernate/fast-start" memory to be lost; the untested update broke the tv.). It sounds like you might fall into this category. I.e., damaged by Roku months ago, but fast-start (which usually causes problems) prevented you from realizing the damage already done.
You can look at home>settings>system>update to see when your tv was last updated. And, look at system>power to see if fast start is enabled. That's probably the start and end of your problem.
You can look at that thread I linked to. Also, look for Roku-Danny & Mary's posts. Click on their profile to see their recent post activity. You'll see there's no help here. (Recently there was a captcha added to block bots. I noticed they stopped posting at that time. Now the captcha has been removed. They're posting again. I don't know. Just saying.).
You're probably screwed now.
Some people have fixed their perma-recovery by connecting to a different network (maybe a phone or laptop "hotspot", or take it to someone else's house. Make sure you tell them it's something Roku thinks is normal for their tvs). Or, just rebooting their own router.
Someone else said they fixed it by unplugging the tv, and holding the power button for a minute to drain the electricity stored in the tv. Then hold the pinhole reset button on the back of the tv, plug it in, and continue to hold the pinhole button until the front light flashes or dims (about 15-20 seconds?). If you could get to the initial setup that way, you could try telling it you'll connect to the internet later (but don't), and see if that fixes it. (The network-less software is lighter, seemingly older, less problematic. You could stream through HDMI this way while protecting the tv from future untested updates.).
But, for many people, none of that works. Roku won't have an honest conversation about it. So, you should prepare yourself for the likelihood you'll have to buy a new tv (unless you still have a warranty. Then, obviously, assert a claim.).
I wonder where that guy is who said yesterday "don't be angry, Roku's good stuff; be patient" (loose quotes).
