Dear Mitch S4711,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
Based on your description “Unable to edit checked out documents in SharePoint even though i have permission as owner” You may try if below method
Please make sure that the Office App should be "Microsoft 365" version. The other versions do not support "check out" feature and have to upload file copies.
https://support.microsoft.com/en-us/office/check-out-or-check-in-files-in-a-document-library-acce24cd-ab39-4fcf-9c4d-1ce3050dc602

You can check your Office client version from **"Word" App >> file >>**Accounts.
If you are already using Microsoft 365 version, please check if there is any update from same page "Office update" button.
Please also check if your Office client sign in account is the same one as SharePoint.
At the same time, you can try below steps.
- Sign out of all accounts from Office App.
- Close All Office Apps
- Clear file cache from
- C:\users<username>\microsoft\office\16.0\officefilecache
- Then restart Office App and reactivate it with SharePoint account.
If there is any misunderstanding, please feel free to correct me.
Have a nice day!
Best regards,
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