Level 1 is warnings, not errors. It's not something to be fixed. ENSLIB and HSLIB are supposed to be readonly. So this can be safely ignored

You cannot change the priority of indices.

You can ask IRIS to ignore particular index -- %IGNOREINDEX, or disable index for a particular condition -- %NOINDEX

You can force join order with %INORDER hint

https://docs.intersystems.com/iris20253/csp/docbook/DocBook.UI.Page.cls?KEY=GSOC_hints

Generally, if you see that some query does not use particular index, that should be used, or chooses bad join order -- collect table statistics, if this does not help -- contact InterSystems Support (WRC), or post details here -- the query, its plan, and describe what plan you'd like to see

If the CSPGatewayLatency is almost 5 seconds -- ignore, this is false positive, fixed in 2024.1.2. Or better -- upgrade! ;-) https://docs.intersystems.com/iris20241/csp/docbook/changes/index.html#CSPServer_DP-433569