it is precisely the current situation of old coins that will have the potential to increase in price. although new coins sometimes have an interesting hype, the market for new coins is not as strong as the old coins. the hype will quickly dissipate and it's just a matter of correction.
but seeing the newly selected coins is also important. because not all new coins we can control. Good analysis of the market and community is very important. because in the current state of the market almost all new coins get upgrades. but we can look for the best.
I suggest focusing on BNB and ETH, they will provide interesting long-term benefits for you.
You need to have your deeper assessments before taking your steps, there's always good and bad sides for this matter, buying old coins that don't have any progress will risk your money, if there's no movement and there's no updates from the developers, staying away is the best thing to do.
With your suggestion, I agree that this two old and working coins are good for long-term investment, the potentials are high not even the value already risen but the chance to see more is very possible, with those working platforms and community appreciations this two coins still have big room to grow.