For investment, I don't see Litecoin or any other altcoins that is not among the top 10 most performing altcoins on coins market Cap as good investment, because crypto investments need long term to yield good profits to investors but, still we should not forget the high volitility and lack of consistency in some altcoins market infact most of the lack the utility demand to keep their market active., this is why it's hard to see sustain market buildings up with altcoins Litecoin price have not gone half it last all time high price.
LTC used to sit in top 10 for many year before dropping into the top 20 like it is now. So judging whether altcoin is good investment based only on its current market cap ranking is not really enough.
However you are right. Altcoin market lacks stability and real demand in a lot of cases. So which alts to invest in is still a personal choice. Its pretty hard to give anyone a specific recommendation.
To reduce the risk, I'd say OP should focus on projects with clear use cases, real demand, room to grow...