I'm using Cloud.
I tried to use the NextGen project because I liked the Roadmap view. But there are to many things missing. Like quickfilters on the Roadmap bord.
What is the best way to get the Roadmap view in classic projects.
It's not available, but there are some options:
I'm sorry to tell you that the Roadmaps feature is only available in next gen projects and will not be available in classic in the foreseeable future.
The features you are missing in next gen will gradually be delivered or replaced with newer, more powerful experiences.