Using awk or sed or any other command line tool re-arrange a csv file as such

Original data of the csv

head -5 persons_db.csv
id, user_id, provider, uid, extra_data
1,    2,     3,   4,       5

Now I need the csv file to be

id, provider, uid, extra_data, user_id, created, modified

so column 3 needs to be made column 2 in the new file, column 4 in the old file is column 3 in the new file, etc and in the new file 2 new columns were added called created and modified. fill those columns with 2021-09-19 00:00:00+00 for every row