I suggest to focus on bitcoin. Bitcoin is the best coin in the crypto world, and the price will most likely be higher after the halving occurs. If you want to focus on altcoins, then Ethereum is the choice. However, I'm sure there will be many people who suggest choosing bitcoin over other altcoins.
I think it's too late to buy bitcoin when the price has already reached the value of 68 thousand dollars and is very close to its ATH. It is better now to just watch how the record price level will break through and then make a decision either to buy Bitcoin or to open a short position.
Not too late like I believe, one thing I believe if Dcaing is that every entry price remains profitable as long we are capable to hold for long. The market will surely often experience some corrections creating opportunity for anyone who missed the opportunity of accumulating enough Bitcoin in his/her portfolio even those who had bought may even want to buy more but in a much softer practice.