I'm having trouble understanding the netsuite help docs on this- can you trigger a user event script (afterSubmit) from a scheduled workflow?

userevent scripts are like database triggers on records. any processing done on records will trigger UE scripts unless you specifically exclude that script type from executing UE scripts.

Is the key that I need to set the Trigger On to afterSubmit? It's currently set to Entry

When I need to figure stuff like this out I set up a script with all the events and log which one was triggered.

/**
 * @NApiVersion 2.1
 * @NScriptType UserEventScript
 */
define(["require", "exports", "N/log"], function (require, exports, log) {
    "use strict";
    Object.defineProperty(exports, "__esModule", { value: true });
    exports.afterSubmit = exports.beforeLoad = exports.beforeSubmit = void 0;
    var beforeSubmit = function (context) {
        log.debug('beforeSubmit context', context.type);
    };
    exports.beforeSubmit = beforeSubmit;
    var beforeLoad = function (context) {
        log.debug('beforeLoad context', context.type);
    };
    exports.beforeLoad = beforeLoad;
    var afterSubmit = function (context) {
        log.debug('afterSubmit context', context.type);
    };
    exports.afterSubmit = afterSubmit;
});

^ This is a great utility script to keep handy. I have a User Event and a Client script version that I keep for rapid deployment