Those „eggs” are not eggs, but cabbage aphids at different stages of maturity. They feed exclusively on brassicaceae, so other non-brassica plants nearby remain safe.
In dry summers they can cause severe damage and multiply very quickly. Like all aphids they suck the plants’ sap and when the infestation is severe, cause the leaves to shrivel and prevent ...
It looks like a crab spider of some kind. There are lots of kinds.
Here are some links with pictures that look like yours:
https://naturegardensnhm.blogspot.com/2012/02/killer-legs-crab-spider-wins-prize-with.html (This one's a white-banded crab spider.)
Supposedly, crab spiders can change colors (so, ...