Hi Don,
I tried using gam user <Manager Email Address> update teamdrive <Shared Drive ID> copyrequireswriterpermission false but that seems to just set the top level setting. Please note that for the option copyrequireswriterpermission false, false = ticked. So I think this setting needs to be set on each file, unless there is a way to set this recursively.
gam user <Manager Email Address> print filelist select teamdriveid <Shared Drive ID> fields id,name,copyrequireswriterpermission todrive will create a Google Sheet of the files in Shared Drive. I have added the name & copyrequireswriterpermission fields so that you can review the Google Sheet if needed.
gam csv gsheet <Your Email Address> <Google Sheet ID created from Above Command> <Sheet (Tab) Name> gam user <Manager Email Address> update drivefile ~id copyrequireswriterpermission false will then change all the files in the Google Sheet created above.
If you are happy with these 2 commands then you can combine together as gam user <Manager Email Address> print filelist select teamdriveid <Shared Drive ID> fields id,name,copyrequireswriterpermission | gam csv - gam user <Manager Email Address> update drivefile ~id copyrequireswriterpermission false.
This should work and do what you want, but please make sure you are happy with it before running.
Cheers
James