Corrupted spreadsheet when reopened

Not really a question, I just need to vent.

For context - I’m in the process of moving our (my wife and I) budget spreadsheet from Excel to Libre Calc so I can throw Windows away. (Excel is really the only product keeping me there.) The spreadsheet has evolved with a lot of VBA code to make updates with fresh data from the bank easy and give me the charts and views that I want. I’m taking a different approach with the calc version and essentially rebuilding it from scratch so I can avoid including any code. I’d like a workbook my wife can use and maintain if necessary. I have imported some sheets from Excel, but no code, and I save it in the native .ods format. I do have a lengthy IT background so I’m running both systems in parrallel with a view to full cutover at the EOFY.

I had a corruption problem on two sheets of the file last night. (Screenshot of the repeat occurence below.) This was while I was working on it, not as a save and reopen. I’d done quite a bit of work since my last save as so I didn’t want to just go to backup if I could avoid it. I retrieved one of the sheets from a backup and copied it into the file I was working on. Changed all the named ranges, repointed chart data series, and patched up the rest. Deleted the remaining corrupt sheet and redid some missed pointers to what was now an external file. Probably a couple of hours work. Saved and shut everything down.

Reopened this morning and the same thing has happened. Screenshot of the main problem sheet.

I do use a virtual Google drive for my files but I’ve never had issues with corruptions using it and the first occurrence last night was while editing, not on a save and reopen. I’ve checked the Libre Office temp and backup files to no avail, so now I need to decide whether I bother going through the trouble of repairing it again, knowing a recurrence is a very high chance, or whether I abandon Libre Calc and just stick with my Excel system.