Is there an entry in Text Replacement for roku?
If so, swipe the entry to the left to delete it.
If not, then the iPad might have decided (based on past learning) that roku is a misspelling of (roku).
You can try to eliminate it by going to Settings > General > Reset > Reset Keyboard Dictionary. This is where the iPad saves auto-correct actions it’s learned from your behavior. For instance, if you’ve often corrected roku to (roku) the iPad may have learned this as the proper spelling. Keep in mind that words you are used to having corrected for you may no longer be automatically corrected.
You can also turn off Auto-Correction in Settings > General > Keyboards. This will stop all auto spell corrections, but not the Text Replacement. Note there is a separate Auto-Correction for physical keyboards under Hardware Keyboard in the same place.
Some apps, like Pages, have their own auto-correction and spell detection settings. Those have to be changed in the app’s settings.
One last thing. For rare and troublesome words that keep correcting themselves (and are not worth reseting stuff) you can let the correction happen, then position the cursor to delete just the unwanted letters or symbols. You need to type something after the word before editing, otherwise it will correct again when you type a space after the word.
