Matic can be a turning point of investment. Besides, Ethereum, BNB, DOT, ADA can be good choices also for getting a good amount of return
Matic may consider for long term investing but you mentioned top coins ether, bnb, dot ada! I agree that those are best suggestions but Op already know about those and he wants to investing except those top coins because those are already grown a lot. That's why i suggested him "he cloud better consider Ftm & next" among the list of altcoins he mentioned as well as sandbox, cake & others
We can add some options to the choice of other altcoins but many investors stay on top coins for reasons of certainty of rising in a bullish period, because there is no guarantee that other altcoins can survive after the bear market has passed.