Hello Tom HEX_200
Thank you for posting in Microsoft Community! We are happy to assist.
We are sorry to hear that you are facing a challenging trying to turn autocorrect on in the New Outlook. let's work together to have that sorted out for you.
The autocorrect in the New Outlook, it has been renamed to "Editor".
Once you open a new message, you can click Options > Editor > Open Editor
Here is how to get to that based on your ribbon view (Simplified or Classic)

an extra panel will open to the right side, showing the editor details
Under correction, you will see the issues that the editor is suggesting a fix for, as shown below

I hope the above information will be helpful. Please feel free to let me know if you have any other concern or if I get you wrong. Glad to assist you. We sincerely appreciate your patience and cooperation. Thanks for your precious time!
Note: Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution.
Best regards
Community Moderator