Additional features, settings, or issues not covered by specific Microsoft Teams categories
Hi Sharon M. Walch,
After researching and consulting, we find it is a known issue that renaming a channel in Microsoft Teams does not rename the corresponding folder in SharePoint Online(channel in Files tab), besides, the legacy OneNote tabs created during public preview of Microsoft Teams cannot be renamed or deleted either, for detailed information, please refer to https://docs.microsoft.com/en-us/microsoftteams/known-issues#channels
Under the circumstance, we recommend you to delete and recreate channel as you mentioned, before which please back up your data and file, after 30 days, the deleted channel will be deleted permanently, and it won't count towards the 200 channels per team limit.
I fairly understand these limits affect your work a lot, our engineers are working on these features, please monitor the updates, in addition, welcome to post your feedback to Microsoft Teams UserVoice, which is a forum for the development engineer to collect feedback from customers, your voice is helpful for better using experience.
Thanks for your understanding and efforts.
Best Regards,
Betty