At first you said you prefer the convenience of a script-based solution so that the clients could create their own ads - but then you said you are the one who is going to be running it yourself?
If after all you don't care about the client running a script, you can use the native Photoshop feature called "Variables" and you can do everything you wish with just Photoshop, Excel and nothing else required, no scripting unless you have some highly-advanced circumstances.
So the following would be my answer if you're the intended user.
Scripting is recommended for if you're already inclined that way, but if you already have your hands full with other things and need this component into your workflow very fast from today, then you may want to check out the native feature. In fact, even prior to creating your own script it could be useful to view a PS variable-data tutorial and run your own mock design with some fake data through to get a sense of how PS handles its variable artwork and a hint of any potential scripting work to be involved.
Even if this workflow is for the client...
Having the native alternative as a talking point and choice for the client could be potentially a method to upsell your custom script since it is more work but could be well-worth it.