I'd suggest you to contact sales to learn the details of custom licensing options if you haven't already, also to make sure you're understanding the active users correctly for your case.
It still offers an open source option so you can test all its limits and see if it fits your case or not. Also if your project is not proprietary there is still the free for open source option in case your project is not compatible with GPL2+.
How I love this comment. I do socials for CKEditor and read almost everything there is to read for WYSIWYG rich text editing, collaborating.(a little late this time)Feedback, frustrations, feature requests. I'm sad to read CKEditor doesn't cut it because I'm able to see in first hand how much effort goes into it. But I'm not surprised because I still have "I would have never guessed" moments about all the ways people use the editors myself. There is ALWAYS room for improvement when it comes to writing on web and feedback from users like you are crucial :)
My eyesight has been getting worse since I was addicted to reading Agatha Christine at age 14-16. After 14 years the decline has not stopped, this is definitely worth a shot.