Need an SPL to review the time zone on my Splunk instances please. Is it important for these TZs to be consistent with Time zones on all the FWs? Should I really care for time zones to be right on the FWs? Thank u in advance.
I'm not sure there exists SPL to get the local time zone.
The TZ of your Splunk instances do not need to match those of your FWs (or anything else for that matter).
The time zone must be set correctly for the location where the server/device resides. Then it's up to you to ensure Splunk correctly interprets all times from that server/device. That may mean setting TIME_FORMAT and/or TZ appropriately.