I don't believe there's a native solution aside from the link you mentioned or a TypeForm integration, so I built a multi-form slider custom module that I hope to be adding to the Marketplace soon. You can demo it here.
I'm still in the process of writing up the documentation, etc. but essentially you can update the colour to match your brand, add as many slides as needed, update the slider header, content and form... etc. all from the sidebar:
Get in touch (on my new multi-step contact form) if you're interested in a version on your portal. You should be able to add it to a pop-up as well.