I am not an investment experts but what I know is that altcoins investment is not what someone must pick for you, you need to do a deep research about the coins you are interested in and if you finds out that the coins have the potential of doing 10x of your returns on investment, you can go ahead an invest in the coins, it doesn't have to be one to two coins but as many as you can find that has the potential to give big ROI. When you don't do your own research and you take the suggested coins of friends, you have to be ready to bear the risk of losses too.
There is enough altcoin that you can invest in but the best thing you can do is to make decision after you have made your own research because that is the most important thing when you do your own research then you will be able to make decision on what coin to invest in or not, so that you don't invest your coin on the wrong hands because there are a lot of shitcoin that the moment you invest your money the next thing the price starts coming down so you have to make a decision on what coin and how much you invest and what exactly you are getting in return so when you do all the mathematics it will make things more easier for you because when you want to become an investor you have to think like one. We know there periods that your plan will not work but when you are consistent then you will know things to aviod, most people don't even know the things they want to aviod. Ik this game you just have to be very smart.