Well you made the right observation in this regard. Because indeed the best time to enter a new project is after they have finished dumping and the decline has begun to subside and then the line has shown sideways. And indeed that's a better time to enter if we want to start accumulation in the hope of making a profit on the next rise. But that only applies to altcoin projects that have large investors in them. And have a team that is actively developing the project. Because there are also projects that are only made to be pumped and then thrown away without coming back up. Because the project will immediately stop and the roadmap will not be fulfilled.
But before you investing in a altcoin project it is important to think about its specific purpose. Projects with much big investors and active team work have a better chance of doing what they promise.On other hand some projects are only for to make a quick profit and then disappear. So we should be careful about these kind of projects. Make some profit and exit.
If you become greedy and will try to get more profit or money so you can face loss. So make a good research and then enter in project.