xahodo I'm curious how well LibreOffice Writer handles a document of 100000+ words (no difficult stuff stuff in it, just text). We'll see once the story I'm writing is finished (if ever).
I doubt you'll have a problem.
I opened my network documentation from the fall of 2021 just to check. Word count is 187,536. Not much in the way of formatting (headers, footers, titles, text, tables and a dozen-odd embedded Draw Visio-like diagrams). No issues.
I created the original document in 2017 and have been updating it as changes were made to the network, so it has been around the track a few times.