i don't believe you can run view mode on a client event script > page init. so would it be possible to run the CS from an UE script? something like this would work?

context.form.clientScriptModulePath = 'SuiteScripts/xyz.js';

Yes, that should work in a UE's beforeLoad entry point. You can also use the script file's internal ID with

scriptContext.form.clientScriptFileId

Here's a full run-down if you need it: RUNNING CLIENT SCRIPT IN VIEW MODE