Can Maven be made less verbose?

You can try the -q switch.

-q,--quiet Quiet output - only show errors

-q as said above is what you need. An alternative could be:

-B,--batch-mode Run in non-interactive (batch) mode Batch mode is essential if you need to run Maven in a non-interactive, continuous integration environment. When running in non-interactive mode, Maven will never stop to accept input from the user. Instead, it will use sensible default values when it requires input.

And will also reduce the output messages more or less to the essentials.

My problem is that -q is too quiet. I'm running maven under CI

With Maven 3.6.1 (April 2019), you now have an option to suppress the transfer progress when downloading/uploading in interactive mode.

mvn --no-transfer-progress ....

or in short:

mvn -ntp ... ....

That is what Ray proposed in the comments with MNG-6605 and PR 239.