Updated TV to late to latest 8.0. Changed WiFi hotspot password on the WiFi, went to update on TV, but at the Password prompt it didn't give me a keyboard!
Connected my Android phone work Android TV app and STILL did not input characters into password prompt.
Using the Infrared remote I could type numbers and the period (.) which is still a broken thing... Who has number-only passwords these days?
Finally grabbed PC USB keyboard and plugged in, input new password successfully.
TLDR latest OS has no support for on-screen or Android App keyboard in WiFi password dialog.
so this mean, when you try to type into a search bar you do see the keyboard, RIGHT?
This is more like a Gboard issue, and it has nothing to do with the os.
Personally i use Leanback keyboard
https://github.com/yuliskov/LeanKeyKeyboard/releases