From my experience, buying some coins today would be a good move knowing that coins are cheap since we are still in the bull market. I personally filling my portfolio now with coins that I like and of course I anticipated that I will make a profit in the upcoming years. I missed my chance from the past bull market and now I don't want for it to happen again, there's still plenty of time to buy coins in the market. I believe that buying before and after the halving will generate us profit from altcoins but the difference is the amount of potential profit. The lower we can buy is the higher we can maximize our profit.
Finding the perfect timing to buy altcoins can be a difficult task, if you buy too early then the altcoins you bought could disappear or lose their hype before they have any chance to skyrocket due to the upcoming bull run, however if you buy too late then you risk buying at the peak of the movement and lose money instead of earning it, so it is not an easy thing to time the market but if you can do it then without a doubt the profits can be on the high side, personally I am not very good at this which is why I prefer to invest all my money in bitcoin instead.