Continued Problems replacing data

Previously i was advised that my app will break if i try to add a sheet and then move all dependencies to that sheet as their source, and delete my original sheet. I was instructed to instead use the “import” feature on my main sheet to add data. However, even though I am only adding 21 lines of data to an empty main spreadsheet, It keeps failing. I get “page unresponsive”. I attempted removing all but the first collumn and then importing, that didnt work either, and i attempted copy paste. Currently it has been importing my table for 30 minutes and still not successful.

I have now tried making my main table match the exact collumns of the table i am trying to import, and it still crashes

Can you give us a recording of your attempt to import? I think there’s something wrong here.