Make spoolfile searching case insensitive Merged

The way I read this request was the requestor was asking for this capability in the base OS display spool file program's search. Accessible by directly specifying a spool file in the DSPSPLF command, or probably more commonly via option 5 when looking at an OUTQ's spool files, job's attached spool files, or the spool files listed in the WRKSPLF command.

That SQL may work, but it is a very complex solution to having case insensitivity allowed (I'd prefer by toggle) in the search within the DSPSPLF's output screen.

Edit to add another example. The interactive output of the DSPFD command is in a "Display Spooled File" screen. Something I frequently go in here to quick check is if a file being investigated reuses deleted records. Despite 20+ years on the platform I've got a brain block that prevents me from remembering if "deleted" in the associated reuse deleted records line of the output is capitalized or not. The habit I've formed is instead to search for "eleted" and omit having to worry about case sensitivity of the D. Allowing toggle of case sensitivity would make this easier.

This can be even more useful when looking at a joblog spool file as one may not be searching for fixed text of a message ID, but instead for the string that would go into a message field where the case of that data may not be immediately known.

What tool are you using when doing this search? Are you looking for the specific spoolfile or looking for a string within a known spoolfile?
You could use SQL service and change all text to UPPER before comparison with the following:
This will not give you the whole spool file to read, but will give you the name, spool file number and the row and row number where the search string match, just replace MY_LIB, MY_OUTQ, my_search_string and the time fram you want to search:

select O.CREATE_TIMESTAMP,
O.JOB_NAME,
O.SPOOLED_FILE_NAME,
O.FILE_NUMBER,
O.USER_DATA,
S.ORDINAL_POSITION,
S.SPOOLED_DATA
from table (
QSYS2.OUTPUT_QUEUE_ENTRIES('MY_LIB', 'MY_OUTQ', 'NO')
) O,
lateral (
select ORDINAL_POSITION,
SPOOLED_DATA
from table (
SYSTOOLS.SPOOLED_FILE_DATA(
JOB_NAME => O.JOB_NAME, SPOOLED_FILE_NAME => O.SPOOLED_FILE_NAME,
SPOOLED_FILE_NUMBER => O.FILE_NUMBER)
)
) S
where S.SPOOLED_DATA like '%my_search_string%'
and O.CREATE_TIMESTAMP between
'2023-05-08 20:21:00.000000' and '2023-05-10 20:00:00.000000';
IBM Power Systems Development

While not necessarily make it case sensitive, having the "Kind of match" option like is in F14 search options when browsing a member in PDM (STRSEU) would be welcome. I definitely wouldn't want to lose the ability to search with case sensitivity, but having the option to not do so would be welcome.