Yes, investing in Bitcoin is profitable. I think portfolio investment is the right choice. I suggest you invest in Bitcoin and Ethereum. The current price is at a low point. Buying them now and holding them for a long time is profitable.
I agree , bitcoin and ethereum is one of the strongest coins in the market and has a high chance of going up soon. Buying proven good coins is a good move too. Holding such strong and good coins has a greater chance of trading it well.