Never hold any altcoin for long time. It is possible that the coin will be lost forever from all the market, there will be no volume at all etc etc. Because you don’t know what's going to happen within these long time. There are a lot of examples, many coins were in huge boom in 2018 altseason but they don't exist now. Even if they exist, they have no volume.
I agree with you, but there are some good altcoin to hold and make long-term investments, because the price will definitely continue to increase and give us a big profit in the future, for example :
1. ETH
2. DOT
3. ADA
4. BNB
because in 2021 these altcoin have made a new ATH price, so in my opinion these altcoin are very good to be used as a long-term investment, because the price will continue to increase all the time.