Dear B1ackBe1tMatt
Welcome to the Microsoft Community, we are glad to assist you.
We understand that you are experiencing an issue with Excel displaying abnormally in your tablet, and in order to better assist you, we need to confirm some information with you.
We've looked at the interface in an Android tablet and can we ask you that after clicking on the file, this part in the red box is completely missing right?
Are there any additional setting options in the whole interface? You can check to see if there is a save icon in the upper right corner of the entire interface.
Since the display of "Open" is different between the two interfaces, we need to check whether the overall display of Excel on Lenovo's tablet is the same as that on other Android devices. If you can, please take a screenshot of the complete Excel interface and share it with us, for example, the display interface after opening Excel, and the display interface after opening any file.
Also, what channel did you download Office through? Was it the Play store?
If not, you can re-download Office through the Play Store to see the interface displayed.
Install and set up Office on an Android - Microsoft Support
So please reply and share more specific information with us, I look forward to hearing from you.
Best Regards,
Tracy | Microsoft Community Support Specialist