Ask HN: Advice on potential alternative tools for managing supplier SKU data

Disclaimer: I've uhm'd and err'd about asking this here for a year or so, but as it's Friday evening here I'm seizing what's left of the day. Background: For a new project, I am a reseller of items from a single supplier. Said supplier provides a ~25,000 line Excel sheet with SKU info on a sporadic basis. The number of available SKUs goes up and down. The Excel sheet is valid until a newer one supersedes it. I currently take the supplied Excel workbook, keep it native Excel and run various calculations, transformations and formulae across it to make suitable input CSVs for Magento Community Edition, eBay and Amazon. My issue is that the spreadsheet has passed 100MB and the quantity of calculations is making it unwieldy and difficult. File -> Save takes close to 90 seconds (i7 4790K, 32GB RAM, Excel 2016), and Excel is unusable during this time. I'm using Excel because a) the source material and and CSV output for the various platforms are easily made from it and b) I know Excel pretty well. This thing has morphed into a catch-all tool for what I do, and I fear Stockholm Syndrome is creeping in. It's portable at the moment, rather than being spread across 5 different workbooks My question: what should I consider for alternatives? I am coming to a point where I can afford the time to learn a new thing, should that be more appropriate. If Excel is the answer, that's absolutely fine, too -- your advice and feedback is very much appreciated. Thanks in advance, and happy weekend to you. Edit: macOS is my primary platform, I have a recent-ish i5 ready to go with Windows, Linux or something else Intel-y.