I agree with you that we should diversify it means not just focusing on mainstream currencies such as bitcoin, but we can buy something more risky as low market cap coins can grow by 10 times and more very quickly. If you are not fond of risks, you all the same can find altcoin to yourself that has good fundamentals. For example, ADA, DOT, Matic.
The irony is that as btc is at its btc likewise solid altcoins are also at there ATH or standing at there peak value. We need to wait to invest in top altcoins or do some rigorous research and find coins that are undervalue even in current bull run. But top time is when market is bearish, sadly most of us are running away from market when it's the actual time to buy.
many people don't pay much attention to this because they think when bitcoin is corrected all will be affected and they inevitably run away from there without realizing it is a trap when they run away the bull run keeps happening and eventually regrets doing it.
even though if from the beginning you were sure that this was happening, you actually didn't need to bother running away from there and continue to hold on to your beliefs because I think it's useless to run away when it's bearish and losing, but after the value is high they re-enter. this space.