Check oracle environment variables ORACLE_HOME, and PATH. Open cmd as an administrator and then run the following separately:

echo %ORACLE_HOME%

echo %PATH%

%ORACLE_HOME% should output like C:\Users\HP\Oracle\homes\OraDB21Home2.

%PATH% should include like C:\Users\HP\Oracle\homes\OraDB21Home2\bin

If they are not, set :

set ORACLE_HOME=C:\Users\HP\Oracle\homes\OraDB21Home2

set PATH=%ORACLE_HOME%\bin;%PATH%

Run the oradim command:

oradim -STARTUP -SID YOUR_SID

Put your SID instead of YOUR_SID, which is in the command above

If the specified service doesn't exist, run this to recreate:

oradim -NEW -SID YOUR_SID -STARTMODE AUTO -PFILE "C:\Users\HP\Oracle\homes\OraDB21Home2\database\initXE.ora"

Change YOUR_SID and the path specified in the command above. YOUR_SID to your sid, path : "YOUR_ORACLE_HOME_PATH\database\initXE.ora". And then run the oradim command again.

Now you can test SQL Developer