Such questions entail similar answers that can not be fully justified and correctly justified, because many projects today are just the beginning of their activities, and you should give your own assessment of the project.
Yeah, you can only know a profitable coin when it becomes profitable as no one can tell what the future holds for any coin and the only thing we do is to find the strong ones, invest in them and hope for a better increase for them in the long run. The most important thing is to trust the coin you are holding based on what it offers and the product it has, since that is what would make it count as it gets demanded as a result of the solution the product offers.
There are lots of coins, but not all of them are promising and what most of them are good for is just their pump and dump. However, for those who are worth investing in, I always consider the coins that are providing solutions and not just some empty promises or master nodes. I believe that the ones with product will always last since they will be usable and useful to the community in the long run, hence the demand for them.