Yes to part where you can make better profits from new projects than investing in old altcoins because you are the pioneer of the project and if it becomes successful, you will be the one who will get the most profit because you bought their token at the start of the development of the project.
No to the part where new altcoins are best to invest right now. New altcoins are very prone to scam and only a few projects are becoming successful. Many projects only live for months but because of some factors like lack of community, lack of investors investing in their project and the developers themselves, often times it ends up as a scam or a rug pull.
Is it a good or bad idea? Well, in my perspective as a conservative investor it is a bad idea investing into new projects because it's very risky for me and I only have limited budget to use for investing. I'd rather spend my money into old altcoins that has values. Yes the profit might be lower but it's safer than investing into new projects. If you have some spare money then you might try to invest into new projects but I'm not advising it especially if you are a type of investor where you are easily affected by losses.