To me, altcoins tends to be more profitable because you are likely to buy more. Now for instance, u purchase an altcoin worth $100, you are likely to have more of the coin reading from thousands to millions, regarding how the price of the coin is and an increase in price will likely increase ur profit level. Buh an $100 worth of BTC is a very little fraction of it.
But all you need to know is this, investment is a risk, so always risk as much as you can afford to lose. Get enough details on any coin you want to invest on. Even BTC and always follow up updates on market trends.
Agree with you, because the price of bitcoin is already high, it will be difficult to be able to buy in units compared to potential altcoins, it is likely that you will be able to buy in units and can be more.
So when bitcoin increases, altcoins also follow and the opportunity to make a profit will be just as much or maybe even more than when holding bitcoin.
Wherever we invest, there is always a risk, especially with crypto, which is difficult to predict well.
But we also have to know that crypto has a repetitive nature, and it always happened in the past, so don't hesitate to invest in crypto, because when the time comes to increase, it can always happen.