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, therefore if we want to invest to avoid big risks, then we can just invest in Bitcoin, but if you really want to invest in cryptocurrency without being afraid of big risks, then you can invest in altcoin, because investing in altcoin can give us a bigger profits than investing in Bitcoin, but of course the risk of investing in altcoin is bigger than investing in Bitcoin, but my suggestion it's better for you to invest in the top 10 altcoin on coinmarketcap (safer than other altcoin).