Personally i do not believe in selling off my portfolio just because I want to hold some bitcoin. Every token have their own purpose to serve. In fact, there are some altcoins than can be of benefits than bitcoin in the future because they can bring better returns than bitcoin can bring. I will rather look for extral money to invest in bitcoin than sell off my portfolio.
Everyone will have different thoughts, but I'm sure any investment is risky. If you want to make a quick profit, altcoin will always be the first choice for you, but I recommend you only choose the coins in the top 100 CMC to minimize unnecessary risks.
I am not interested in new coins because that investment is often very volatile and often makes me lose so in recent years, I have been very careful when investing.