ADG DML Redirection
DML Can be executed at a Standby with the Active DataGuard Licence since 19c.
Oracle recommends only short transactions (few rows) from a small number of sessions be allowed to use DML Redirection.
If you are using a Sequence for the INSERT, see Oracle Support document : Doc ID 2819996.1
Also see these blog posts :
ADG and DML Redirection https://hemantoracledba.blogspot.com/...
and
ADG and DML Redirection with Multiple Standbys https://hemantoracledba.blogspot.com/...