It's time to up the website flexibility. Make the pages adjustable. We have 4K monitors through cell phone screens. Each user should have the ability to adjust the width of the content to their needs. If an actor plays multiple parts, people should be able to read them, not a small portion.
Are you talking about a single credit with multiple characters, or multiple episodes with a different character in each episode?
If the former, I don't see the connection with the rest of your description. The multi-character line doesn't display all information even in desktop mode: Not on a name page: https://www.imdb.com/name/nm0000092/