Since then, it is impossible to import an excel layer, I have an "invalid data source" message. With QGIS 3.18, i can import this excel file, but i want to work with the new version of QGIS!.

What is the bug? What is the bug or the crash? Importing a csv-File (~12 Mio rows) to Geopackage in QGIS 3.40.2 ignores rows and just imports a little than 5 Mio rows (datasets) - without any ...