Totally agree with you. Doing own research before investing is the utmost important step to do for investors. Some components of projects should be considered during research process: team information (especially in the past, works, achievements, reputation, scam accusations), potential use cases of products from the projects, demands of community and the power of community itself( small or big).
I am glad that you understand the best way to get a very good project is to first of all do your own research, you need to understand what the project is all about and also have a strategy to discern the team.
Yes, it will save a lot of time, and also reduce risks for inexperienced investors. Invest into top 10 altcoins, when they dumped are good, and investors can hold them for months to wait for chances and take profits. It's less pressure of losses to invest in top 10 altcoins.
To save yourself the stress, first I will advise you look into altcoins that are at the top 10, majority of these coins has already bottomed and I think you can invest now, although the top 20 too are not guarantee that they will last for a long time, but for the main tim, they are still on top of their game.