There appears to be no way to filter using an arcade expression.
I added a "virtual field" that is visible in my fields list and pop up, but I am not able to filter by it.
I think it would be useful to be able to filter by arcade expression in order to filter out features without attachments for example. Without having to add a new field to the data.
There should be an expression field that I added in the list of fields, but it is not visible in the drop down for filters.