Issue in Network configuration in Oracle 21c Home

In Oracle 21c, Oracle home is only readonly. Issue occured due to default location of Network folder is changed in Oracle 21c.

Prior to Oracle 21c, Oracle home is same point to single location ORACLE_BASE_HOME and ORACLE_BASE_CONFIG.

From Oracle 12c, To maintain Oracle Home readonly, ORACLE_BASE_HOME and ORACLE_BASE_CONFIG point to different location.

ORACLE_HOME & ORACLE_BASE is same:

Before 21c
ORACLE_BASE=C:\app\oracle\
ORACLE_HOME=C:\app\oracle\product\19.0.0\dbhome_1

After 21c
ORACLE_BASE=C:\app\oracle\
ORACLE_HOME=C:\app\oracle\product\19.0.0\dbhome_1

ORACLE_BASE_HOME is different:

Before 21c:
ORACLE_BASE_HOME=ORACLE_HOME
i.e ORACLE_BASE_HOME=C:\app\oracle\product\19.0.0\dbhome_1

After 21c:
ORACLE_BASE_HOME=ORACLE_BASE\homes\HOME_NAME
i.e ORACLE_BASE_HOME=C:\app\oracle\homes\OraDB21Home1

Network folder or tnsnames.ora files location is changed:

Before 21c:
ORACLE_HOME\network\admin
i.e C:\app\oracle\product\19.0.0\dbhome_1\network\admin

After 21c:
ORACLE_BASE_HOME\network\admin
i.e. C:\app\oracle\homes\OraDB21Home1\network\admin

Refer: https://docs.oracle.com/en/database/oracle/oracle-database/21/riwin/file-path-and-directory-changes-in-read-only-oracle-homes.html#GUID-5E7370F6-632D-4582-A434-6A7D3B57F01A