I'm not familiar with ODBC on Linux, however it seems that Caché is unable to use the configured DNS named "DSN".

Is that DSN properly configured and successfully tested in Linux?

For configuring ODBC, have a look to this "Ask AI" answer.

If you still have issues, I suggest to open a new question and provide detailed information on what you have configured/done and the results/errors you had.

it doesn't seem like the Results of the Class Method are coming back correctly 100% of the time.

This is VERY strange, I would add a test/check if an error occur testing SQLCODE and %msg after &SQL() to see if/when/why it fails.

When using embedded SQL you are not supposed to check/access a returned variable (ExtDisplay in your case) before checking for success/failure via SQLCODE variable.

If you need to check if the query found a row, you should check the SQLCODE value, not ExtDisplay  value.

Stream compression is enabled by default since version 2021.2, see release notes:

Saving on Storage

Stream compression – is now on by default for all globals-based stream classes, with no application change required. Existing data remains readable and will be compressed upon the next write. Experiments with real-world data have indicated compression ratios ranging from 30% for short texts to 80% and more for XML and other document types.