I use and rely on LibreOffice. I just finished my PhD thesis (300+ pages, dozens on tables, graphics, 500+ footnotes) with LibreOffice Writer and I am very satisfied. Particularly Writer I find way superior to MS Word. Calc I find similar to Excel. Impress is also okay.
This helps to get an overview where LibreOffice tops MS Office and where it lacks:
https://wiki.documentfoundation.org/Feature_Comparison:_LibreOffice_-_Microsoft_Office
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