I don't like the idea of splitting your investment especially wen dealing with crypto, I will advice to focus on one altcoin that has potential and invest in bitcoin at thesame time it will be better, bitcoin is guaranteed to reach another ATH and with any altcoin you will be stress free with your investment. There's no need getting jampacked with the market and it gets a little bit confusing with the right investment choice.
Although if anyone decides to choose this investment choice then the person should make a proper research first before buying many altcoins.
You said focus on one good Altcoin with potentials, how then are you supposed to predict accurately that the particular Altcoin will generate profits. The Altcoin market is full of scammers and getting accurately a good project is very difficult so the idea of spreading into three with potentials after close researches will make you stand a chance of profiting from any of them or if one decides to fall out.