I can't predict the future, so I can't say whether BTC will move sideways for the remainder of the year, or will surprise everyone and retest the ATH soon. But based on history, it is more likely that we'll move sideways, thus getting into long term altcoin positions is not a bad decision at this point. Does NOT mean your ALT/BTC pair won't dip 50% from here, but it does seem like that is the worst that will happen, if you can stomach it.
I'm seeing several ALT/BTC charts on the weekly that are extremely oversold. Bitcoin Maximalist gloating is going parabolic. Even the most shitcoin-degenerate folks (also known as "community members") on the internet are starting to capitulate. Buy when there's blood on the street folks! Either you believe it or you don't, but markets do not change as long as humans are fearful or greedy!