You probably don't do the level of graphic embedding that some of the users with problems do. I get the idea that this problem deals with files that are huge ... books filled with graphics, Excel tables filled with a lot of embedded PNG and JPG graphics. However, Office 2013 and Office 2016 use the same framework for graphics.
I realize that this has no financial priority at present, but it might be of some future value, particularly if it's of value to your CV to show you're up and running with the current version of Office. Microsoft sells annual subscriptions to Office 365 for prices that I consider reasonable. Here on the continent it's € 69,- a year for one machine and € 99,- for 5 machines. I have the latter, with my license used for the three computers here. The other two go to the two laptops of my daughter, who's a schoolteacher.Most people who own Office can also afford to upgrade it. I can't. The other reason could be that I've only used Word and Excel with any regularity, and only then to titivate my CV, do a bit of writing now and then, and create purely functional spreadsheets to solve mathematical problems - nothing graphic.
This is not cloud software but rather the full local installation package, with Word, Outlook, PowerPoint, Excel, Access, OneNote, etc. Microsoft keeps your installation always current with updates to new Office versions when they're released.
Again, I know this isn't a current topic for you, but in the future, it might be of value.
I've been there already too. I understand how it is.My situation is such that I can't afford to make any kind of a purchase that isn't food for the foreseeable future, so I think I might struggle to finish my City map and then let it be at that.