Is there a way in Postgres to convert an excel file store in a database as bytea to a table of columns with the real data

Question

I have loaded data from an excel spreadsheet that was located on Gitlab and stored it as a bytea column in a master table. Now I need to create a table which will contain the actual columns present in the spreadsheet and convert the bytea to the actual data and insert into this table. How can this be done? Any ideas will be appreciated. P.S I could have saved the excel spreadsheet to .csv and loaded to DB using the COPY command. But I do not want to do any conversions on the raw data but to store in in binary format till I begin my transformations