Multiple word documents are open simultaneously causing performance issues.

Does anyone know what the optimal size of Word documents should be if you have multiple word documents open simultaneously? I frequently access two Word documents at are about 800KB each. When I have both open, I notice a significant performance degradation when I do searches, add/modify/delete contact, toggle between the documents. This really impacts my productivity. I am wondering I should reduce the size of these files or move them to a different drive or memory stick to improve performance. I don't want to break these documents up yet given that instead of having two Word documents open, I might have four Word documents open simultaneously and still have the performance issues. I have performed online repairs of Microsoft 365 and checked my addins but nothing seems to help.