The file size limit for uploaded spreadsheets is 5MB. If you're seeing the error message
WARNING: This worksheet is too large to import, it's highly likely your file exceeds this limit.
We recommend importing
.xlsx file to Google Sheets. You can then use ImportRange to reference the data from the converted file.
An alternative option is to export the
.xlsx spreadsheet to a
.csv file and use ImportData to import that data into Google Sheets.