Dear Curtsith,
Good day! Thank you for posting to Microsoft Community.
I do understand your query here, but deleting folder in outlook for iOS doesn't seem feasible at the moment, you have to be on a computer (outlook for Desktop or Outlook on the web) to remove folders for Outlook.
As alternative, you can login to your Outlook on the web -->Change your browser to desktop view -->select the folder you want to delete -->Delete.
In the meantime, thank you for bringing this to our attention and forum, your concern is very meaningful and reasonable. So, we will surely raise your concerns to our Product Development Team and hopefully this can be included in the future updates. In the meantime, we sincerely recommend you post your concern as an idea to our Outlook feedback site via Outlook · Community (microsoft.com), our Product Development Team are committed to enhancing the customer experience by continually examining suggestions to include in the design and development of future product upgrades based on your suggestions. Hopefully your suggestion will help many users in the future.
Thank you for your time and understanding. For other questions, feel free to add your post in the Microsoft Community team.
Stay safe and healthy. Have a good day!
Sincerely,
Libeamlak | Microsoft Community Moderator