Will I encounter problems if I upgrade iMac (M1, 2021) from Monterey 12.7.6 to Sequoia?

In the last 2 days my previously perfect iMac V. 12.7.6. will not allow editing or printing of documents in either Word or Excel (which are accessed through a Microsoft365 purchase). Microsoft tells me that its product is now incompatible with my Mac. So I am left with 2 choices:

(1) Buy a new Mac which I do not want to do as this one is only 4 years old and works perfectly.

(2) Upgrade from Monterey to Sequoia so that I can resume using Word and Excel. BUT a few apple employees have told me, off the record, not to do this as there will be problems. I am of a mind to heed this, because years ago a similar upgrade changed my perfect iMac into one that was unusable.

I am not a Luddite, but am equally not VERY tech-savvy, so if you answer me, please, no jargon. I will very much appreciate any help or suggestions, thank you :)