If it's new altcoins you talking about sorry I'm not ready to recommend them to any newbie because they have uncertain future, it's better to prepare for short term holding only, for long term holding bitcoin and ethereum and few other old altcoins are the best option
Indeed new altcoins are not the best variant for long-term investment, if we are looking for projects for the long term, we should focus on top altcoins. l think they have more potential than others. As you above mentioned BTC and ETH are really the best options. ETH price is still high, but l think it will not stay at 1.5k. ETH will start price increasing in the future. We can make good money from ETH investment. l think l don't need to talk about BTC because BTC is the best.