How Can I Get Word Processors to Respect my Font Choices?

A.S. Before we begin, I have sensory processing and coordination problems. I can get migraines from the flashing cursors in LibreOffice, Pages, etc. and have trouble with other bugs in Textedit, so I currently use Bean, which is no longer supported. But I've had the same exact bug in LibreOffice.

If I try editing something, many word processors switch to a "default" font and font size, which I never use, and never used in that doc. *headdesk* Is there any way to fix the document I'm working on? I have rsi, I can't get Dragon to work, and no way can I retype everything. Is there any general way to find all the docs with the wrong "default" fonts and switch them tok the actual fonts?

Since I don't use Word and have had trouble with documents going haywire or crashing because of Word styles, I avoid styles.