This poll banner theme component might do the trick, it uses the numerical score poll built into Discourse, and displays the poll as a banner:
It relies on Discourse’s existing number rating poll functionality.
To use it you have to create a new public topic with a poll in the first post (if you don’t want the topic to appear in the topic list, you can unlist it)… the poll markdown looks like this:
[poll name=example type=number results=always max=10 step=1]
# How likely are you to recommend us to a friend?
[/poll]
Then you’d configure the theme component settings using the ID of the topic (the number from the URL):
When someone clicks an option in the banner, the poll in the topic is updated. After voting they’ll no longer be shown the banner on their current device. You can also configure the banner to show after a set number of minutes (default 20), and can also stop it from showing at a point (default is 7 days).