kirby planet robobot is the perfect entry point for modern kirby because it's just a really good 2d platformer that really shows what makes kirby special while also having a lot to make it stand out from the rest of the series

for zelda, the perfect entry point is ocarina of time 3d
its the perfect summary of what the franchise is all about wrapped up in a really nice package imo
failing that and considering the state the 3ds is in now, a link to the past and breath of the wild are good options too- the former for the same reason as oot3d, the latter because its a great introduction to the new zelda formula going forward