"io.gatling" % "gatling-commons" is published as a Java, not Scala artifact (no scala-specific suffix in the artifact name).
However, the artifact itself depends on Scala 2.13 dependencies: https://mvnrepository.com/artifact/io.gatling/gatling-commons

Those dependencies break Scala 3 project.

Proposed solution: publish all gatling artifacts which depend on Scala as scala artifacts, cross-publish them for Scala 2.13 and Scala 3.