Excel is unusable for large files that link to each other

At that level of data, it’s often easy to kill Excel whether you’re on Windows 10 or macOS.

• Plain data should be fine for hundreds of thousands of rows and less than 30 columns for most data that’s not UUID length.
• What seems to be most finicky is calculations, graphs, conditional formatting and all the processing that happens to the data and not simply the file of 100 or even 500 MB on disk.

The code base for 2020 Excel is the same on Mac and Windows with just some features selectively enabled for each platform. This was unified in the past 16 months, so you would need to simplify your calculations by troubleshooting your spreadsheets or perhaps move to an engine that’s less likely to get caught up like python or R. The main difference on Mac vs Windows is major feature and UI code for each platform, not the core data handling.

Depending on your linking, you might also just need a database which can handle indexing and optimization better than Excel can.

These are not at all trivial suggestions, so I know you’d prefer to not fix Excel, but it has so many layers of features, that you can stray away from performance and end up with a very fragile workbook in practice. There’s only so much stripping of charts and data you can do in some cases when you overload Excel with code and graphs and conditional calculations or worse, looping conditions that it cannot self detect or alert you.