Writer Slow with Big Files

Hello everyone! I’m having my first experience with LibreOffice, having bought a laptop with Endless OS and LibreOffice (6.3.4.2) installed by default.
I have figured most issues that arrived from my inexperience with the writer, but I still have one problem, the Writer is working very slowly when I try to open large documents (.odt and .docx) with it, to the point that it becomes unusable. It takes several minutes to open or save a 866kb document (just plain text), and the program stops responding regularly, especially when recovering lost archives.

I have searched elsewhere on the internet, but only found old answers that suggested doing things that are apparently no longer available in this version of the program (or at least I couldn’t find them), such as turning off OpenGL and increasing memory usage. I also tried turning off JRE to no avail.

Does anyone have a different fix that can help me?

Thank you all!