I have set the type colour, size, and background on my Netflix account but that is not what appears on Telus Optik TV. Also, quite often, the subtitles disappear too quickly particularly when they are difficult to read in the first place with white text on a white background. Any help is much appreciated.
Double check that the settings in the Optik Netflix App have these same options as well. The two apps are not connected, so it is possible the changes you have made in your Netflix account are not transferred.