Hi kelly,
I only have trial environment thus I couldn't test with Event Portal for you.
However, as event website is still built on Portal(I have Custom Portal), so you could try to add a new page like what we do in normal portal.
In Portal Management app:
1. Add a web page record.(set a Partial URL for page)
2. Create a page template:
3. Add your custom HTML and javascript code to a web template:
In addition, from code of deployment script,
it seems that the script would only update/upload following files:
* font libraries
* translations files
* necessary javascript files for main function
* global style.css
In my opinion, operation that editing component files such as appModule.ts or routes.ts would be more related to self-hosted deployment.
In a word, you could try to do it within Portal App.
You could also take article below as reference:
https://pkoval.com/2019/04/07/extending-dynamics-marketing-event-management-portals/
Regards,
Clofly
