I can move around in sheets but I can’t get dictate to work. It works fine in docs.
There is a bug in Chrome that requires a couple manual steps to get all the functionality there. Please go to “chrome://apps” in your address bar and remove all of following that you see there: Google Drive, Google Docs, and Google Sheets. After that it will work.
Your browsing won’t be affected. Chrome Apps are officially deprecated as of a year ago and interfere with extensions.