Several suggestions:

• GitHub has a feature that allows for automatically deploying Maven projects (among other types of projects) to a built-in Maven repository, which could be used to replace TARDIS Jenkins. They are called GitHub Actions and GitHub Packages.
• Use the "SNAPSHOT" suffix for the Maven version to make it clear that the version is still in development. When versions have no "SNAPSHOT" suffix, it suggests that they are releases, and are unchanging.
• Make a release on GitHub whenever the version number changes.