I have a Mac so if I wanted to use a free software I would just use Pages, but ms office is included at my college and it has useful ai features and citation extensions. Most professors also require that slideshows and spreadsheets be in excel or pp format.
Do these professors state a reason why files need to be in a proprietary formats? Or what would be done (by them to students) if files were to be in a FOSS formats? You can save in the PPTX/XLSX format with LibreOffice suite.
We only need to provide a PDF file so I can use whatever I want.
Ask professors if they know that you have to pay to use MS Office suite. So you can argue that you won't pay money to be able to make documents/spreadsheets/presentations.