Help with simple check for Oracle Dataguard on 19c

I am new to Oracle and needing help just getting a quick script to check Oracle Dataguard. Do any of you have a simple script that could be used to just give me a quick status on dataguard? Just a quick check, if dataguard is in sync or not. I was given the below query, and it appears the script just simply tells the log gap count between the primary and stand by. Does that seem reasonable or is there a better approach? In this case, if the log gap is more than say, 3, then dataguard needs to be investigated?

select LOG_ARCHIVED-LOG_APPLIED "LOG_GAP" from
(SELECT MAX(SEQUENCE#) LOG_ARCHIVED FROM V$ARCHIVED_LOG WHERE DEST_ID=1 AND ARCHIVED='YES'),
(SELECT MAX(SEQUENCE#) LOG_APPLIED FROM V$ARCHIVED_LOG WHERE DEST_ID=2 AND APPLIED='YES');