@ryanmiller
Some projectmanagement options that come to mind, albeit not feature complete for your question:
#LibrePlan https://www.libreplan.dev/
#GitLab https://about.gitlab.com/blog/2018/03/05/gitlab-for-agile-software-development/ (5 year old article, new features might exist)
#WeKan https://wekan.github.io/
#NextcloudDeck https://apps.nextcloud.com/apps/deck

Perhaps you can use API's or the data access as a source for other features like a Gantt chart. Some Python scripting might be enough to get the missing features in place.