Big props here to Amazon Prime Video for allowing you to open an Amazon app you've already logged into on a device with a camera and scan a QR code on your television to log in, rather than requiring you to type a password using arrow keys to select from a virtual keyboard.
I was just using the Roku app on my phone for this. I don’t know if it’s universal for apps on the Roku, but it certainly is nice.
Hulu also allows you to type a short character sequence from a website instead of using a password.
It's even worse with Apple TV, where you have to swipe between characters on a single row. They completely butchered UX on that one, it's infuriating.
If you have an iPhone, you can use the Apple TV remote on the phone which will show a text input you can type on (on any form text input). This has the added bonus of being able to access your keychain for automatic password filling
I have enabled the tv remote on control center - I’m not sure if it’s there by default. You should be able to toggle it in settings
I’ve found voice dictation surprisingly useful in these situations - you can instruct which case to use as well as using military alphabet.