You can add the files variable to an empty array, then remove null values.
e.g.:
{{ remove(add(emptyarray; 214.file1; 214.file2; 214.file3); null) }}
Output
(if there are only two)
Hope this helps! Let me know if there are any further questions or issues.
— @samliew
P.S.: Did you know, the concepts of about 70% of questions asked on this forum are already covered in the Make Academy. Investing some effort into it will save you lots of time and frustration using Make later!