Is there a way to restore the Categories sheet in Google Sheets or get a fresh one? I mistakenly inserted and deleted rows, which caused the formulas to stop working correctly. I don’t want to restore a previous version and redo all the sheets, as the Categories sheet is the only one with issues.
I think you can use the Previous Version tool to ‘make a copy’ of the old version. You can then copy what you want from it to the new version, then delete the old version when you’re done.
Another way to make this change would be to delete the categories sheet, monthly budget sheet and yearly budget sheet and then restore the yearly budget since the categories is a dependency it will be reinstalled, like Randy mentions in this post Restoring the "Categories with Budget" Sheet - #4 by randy then you would need to redirect the transactions sheet category column to look at the new categories sheet.
Consider Troubleshooting the Category dropdown in the Transactions sheet followed by the Data Checker Tool. 