Timeline data structure

Hi, i want to fill in a timeline from Make.com
but cant seem to figure out the data structure

I have followed this solution: Timeline structure for subitem Integromat
And it works if i delete the “Timeline” part
but then if i ad it as milestone, the milestoner checker doesn’t work

it looks like this

when it should look like this

I get an error when i send this (i map the visualization_type first)