You can display Popup by User Ids using the Post Grid Combo plugin. This article will help you to display a popup by user IDs.
To begin, insert a “Popup” block.
Click on the Visibility Tab and click on the Add Group button.
Then Click on the Add Condition Button to add a condition to load the Popup by user IDs.
Here, choose the Click Right option to make the popup display by user IDs.
Now, insert user IDs to display a Popup for those users.