help adding and deleting nested array elements in v4

[olets]

I'm moving my project git-replay from yq v3 to v4, and am having trouble finding the correct new syntax for two things.

Working with a file like

# myfile.yaml
array_1:
  array_2:
    - array_element_1
    - array_element_2

in v3 I would use

yq d myfile.yaml array_1.array_2.array_element_1

to delete array_element_1 and

yq w myfile.yaml "array_1.array_2[+]" array_element_3

to add array_element_3.

What's the best v4 approach? Thanks!