I think that it is not necessary to sell not one of these cryptocurrencies, and if you build, then only buy Ethereum if there are extra finances.
This is a fact that the price of ETH is soaring and we are approaching the lowest value in the history of the year but if you are already holding ETH, do not trade it for Bitcoin or another coin because of the down price of ETH. The price can also drop down to the lowest as a result of the Whales activities as well. But irrespective of all the depreciation, the technology is very advanced and it will bring around fruits in future.