Solved Windows 11 Theme Overrides MS Office Personalized Settings -- How to Prevent?

I have created a custom Windows 11 Theme. It has changed my screens the way I wanted. However, I would like MS Office, especially Excel, not to reflect the Theme's settings. Is there a way to keep that from happening.

I have went to:
Excel\File\Options\General\Personalize Your Copy of MS Office – and made various changes.
None of the selections made, have changed Word and Excel docs and spreadsheets. Their text and backgrounds are the Theme's settings.

Is one stuck with having a Win11 system Theme displayed in MS Office sheets?

NOTE: MS Office Home & Student 2021 is being utilized.

Additionally, I found the following on MS:

• You can use one theme in Office and another in Windows, or have Office match the Windows theme. It's your call.
• To set your Office theme:
• In an Office app, select File > Account.
• From the Office Theme dropdown, select the theme you want.
  If you select Use system setting, your Office theme will match your Windows theme. Note that the Office Theme box will appear empty if you haven't already set your theme.

I've followed the above instructions. But still no change to Word & Excel (using the above) and with the various Window's Theme's I have selected. My supposition is that I'm missing something or doing something that is causing my dilemma. Any ideas of what can be done, if anything?

Ok, maybe I've answered my own question. Perhaps a high contrast Theme overrides MS Office settings. Because I selected a Theme without high contrast and the above MS instruction work as described. Have I found the key?

Yes, I believe you answered your own question...and one I've tried to answer as well. I spent a long time building my own theme and finally gave up on getting Office to follow my settings. Being unfamiliar with css I resorted to using Windows 7 to build my theme which had to be built as high contrast to get it the way I wanted. Thank you for reporting back as that issue with Office has nagged at me for months. I never considered the high contrast aspect played into it.