Of course they are risky. We know the traumas on Altcoins in the past, FTX, LUNA, these have created big crises in the crypto market. Coins such as BNB, ETH, or the coins you mentioned, which we know as solid altcoins, are going through the recovery process, of course, depending on bitcoin. When the market trend reoccurs, I can say that I am hopeful for alt coins, but even solid coins are just as risky.
I agree with you, that solid altcoin also have risks, so not only new altcoin, but old altcoin are also at risk, so in my opinion all altcoin have the same risk, therefore if you want to invest in cryptocurrency for the long term, then Bitcoin is the right choice, because all altcoin prices depend on the price of Bitcoin (Bitcoin is the king of cryptocurrency).