Any alt coin suggestion expect ada.In my point of view of ada still can't surpass ETH in the smart contract field and even if they can make it will be hard to be replace existing eth smart contract eco system.Moreover late coming project like sol even surpassing to ada,all things ada have is the loyal user base and nothing special things in tech
I personally will invest in ETH and BNB for the long term, because in my opinion ETH and BNB are blockchain projects that will definitely continue to grow and survive all the time, so it is very safe to invest in ETH and BNB, especially if you make ETH and BNB an investment. long term, then of course you will definitely get a lot of benefits from investing in ETH and BNB.