Do you see anything at all? If you press left-arrow to the guide, do you see any overlay messages? (If you change channels, do you see the channel number displayed?) Does it look like a dead screen, or just no picture?
Try home>settings>system>advanced>factory-reset. During the initial setup, tell it you'll connect to internet later (but don't do that). This loads a minimal (older) version of software. Then go to antenna tv and scan for channels. See if that works. (I'm actually running my two tvs that way because the antenna tv interface is easier to use than the new version.).
Roku's untested updates cause a lot of problems. I'm inclined to think that did it. But, it could be a hardware problem. Or, maybe your antenna went bad (if you're seeing channel numbers displayed, just no picture).
"People are often amazed at how much we’ve done with the number of engineers we’ve got." (Roku CEO Anthony Wood, Austin Statesman, Oct 4, 2019). "Amazed" is one way of putting it.
