Not all altcoins are having a bigger rise this year.
Most of them are dropping down and some are actually losing their value. Only top coins are increasing and not every altcoin have the potential to rise better when the bull market runs.
It's still best to invest with Bitcoin because the changes are visible.
It's actually dizzying the amount of alts out there and not even 10% of all those are gaining value in the past couple of months despite some alts soaring as high as 200%. I noticed most of the most popular once have even decreased in demand and value. so maybe yeah, I'd rather stick to btc for a while and calculate and learn more about alts I might decide on getting.