I have a current project that I would like to change to a Next-Gen project so that I can use the roadmap feature. Is that possible?
Not yet, see the earlier question https://community.atlassian.com/t5/Jira-questions/Moving-all-tickets-to-different-project-for-using-the-new/qaq-p/922677
It looks like you're new here. Sign in or register to get started.