You can embed a Mendix app in Active Workspace using an htmlPanel in your XRT, e.g.
<page title="ERP" visibleWhen="structure_revisions==null and ActiveWorkspace:SubLocation != com.siemens.splm.client.occmgmt:OccurrenceManagementSubLocation">
<section title="Information">
<htmlPanel src="https://someapp.mx.lowcode.siemens.cloud/erp/info?item_id={{selected.properties['item_id'].dbValue}}" enableresize="true">
<property name="item_id" />
</htmlPanel>
</section>
</page>
However you will face an authentication challenge from Mendix when you access it.
You will also have to deal with security complexities for your app to allow itself to be embedded