Using classic Outlook for Windows in business environments
https://www.reddit.com/r/Outlook/comments/1492891/turn_off_paragraphs_markssymbols_in_outlook/
- if you're replying, open up your draft in a new window, or just click new mail so it pops out into its own window, then Ctrl + Shift + 8.
https://learn.microsoft.com/en-us/answers/questions/2242318/outlook-keeps-showing-formatting-marks
- Did you try all the steps in the reply you got to your Q&A post?