Are you sure you want an enum when it has that many values? Did you consider using an associated entity?
That makes it easier to fill it with values, and allows you to more easily change the values in the future.
The easiest way for me would be to create JSON or XML file with the 1000 values and do the import of those values in separate entity. With Import Activity “Import with mapping” you can easily do the import.
Make a relationship to your entity and in your page create a Input reference selector and you are done.
Hop this helps you,
Use an associated entity instead – you can even prepare an excel import microflow with all your date with the exel import module from the app store
But what if you really want to create 1000 enums? I think its time the expose the Mendix SDK functionality in the modeler itself, so you can generate a model in a microflow and download the mpr lol