I’ve tried open office, Google docs, libre Office… I’ve always seemed to have issues with compatibility when someone opens my file (saved as a DOCX by one of these programs) in Ms Word. Paragraphs will be misaligned, fonts are different, headings not recognised etc… I’ve been using OnlyOffice recently. I haven’t had any issues yet. Limited fonts though.

LibreOffice is probs the major alternative.

I second libre office. Depending on your needs you may want something more specialised if you’re working on something really big. Scrivener isn’t free but it’s made for writing things like research papers and novels.

There’s also a program called Joplin that’s a good evernote replacement

Open office