I found the answer to my question

Hello, as a newcomer I chose $DOT for my investment, and I bought it at the lows, and then it dropped even lower ))). I came to the spot to enjoy the local movement, and everything was fine, I made a little profit, then lost a lot more during the drop, it's normal, movement.
But observing the chart of $BTC and the chart of
$DOT I notice that they move almost in unison, the charts of other coins similarly jump along with Bitcoin. It seems there’s no point in buying anything else besides Bitcoin.