A question came up recently concerning whether it was still possible to connect to .xlsx Excel files as SQL Server linked servers.
Short answer: Yes, it's possible as recently as SQL 2019 using ACE.OLEDB.12.0 provider.
Medium answer: Yes, but linked servers from SQL Server to Access and Excel are only supported when using the deprecated 32-bit Microsoft.JET.OLEDB.4.0 OLE DB provider.
Long answer: Yes, but this shouldn't be part of any automated ETL process, please please engineer around using Excel file interchange in any automated data ingestion processes. That said...