You should be able to extend the if: to something like this: ${{ (needs.changes.outputs.packages != '[]' && needs.changes.outputs.packages != '[something]') }}, or fix up the changes job to omit the ‘something’ package from the output, either up front before the changes output value is populated (detected changes to an env var with a variable substitution dropping something from the list) or by manipulating the changes output values as a final step in the changes job with a sed or whatever and updating the output with that outcome with another run: echo "::set-output name=changes::blah,blarg" which would replace the existing values.

Then the subsequent job conditional stays as-is, the exclude can be dropped from the matrix config.

You could also add the project path that you never want this workflow to run as part of the on: block:

on:
  push:
    paths-ignore:
      - 'something/path/**'

Then it just won’t ever trigger on changes to anything in that path. Which is way cleaner than triggering the workflow and running the changes job unnecessarily.