can we set values on afterSubmit (UE script) using context.newRecord > setValue or must the record be loaded first before setting the values?

I don't believe so. I've always had to submitvalues to the record, or reload the record, update it, and save it.

try it! what happens when you do it?

yeah, had to load the record, set value, then save

You don't have to do that unless its a sublist value. Submitfields will do it and takes less governance.

Or don't use afterSubmit