It depends on which alts you go in to, but many of them are starting to pop off now. They are all inherently higher risk/more volatile than BTC at this point, thus the potential for more insane returns.
Last bull market felt like there was a very limited amount of spots for projects to do well, i.e. in the top 20 to 50... maybe 100 coins. I have a feeling as crypto grows even many hundreds of blockchains will be booming for a while as long as they have solid fundamental technology and a dedicated community behind them to provide proof-of-value.
The tricky part is navigating from BTC --> alts --->BTC --->fiat, etc. in the right timing. I majorly failed on that last bull cycle, lol!