Hello Carrara,
Hope you're doing well.
There are some Forge components to export HTML tables to an Excel file. Did you take a look for example at these?
Dynamic Excel Report
Reactive Export as Excel
They are both for Reactive Web Apps, OutSystems 11 and they have demos so you can see how to implement it.
According the description, it seems that they do exactly what you pretend... Meaning export to Excel the information that is displayed on the screen.
Anyway, you can always export data to Excel in a Reactive Web App using a Server Action.
You just need to create a Server Action, where you should pass your List (information to export) to a RecordListToExcel action and assign the result of it to a Binary output parameter. After that, you may call this Server Action in a Client Action and pass the Binary output to a Download node. You can check in this documentation how to do it.
Hope that this helps you!
Kind regards,
Rui Barradas