Insert multiple items at multiple Indexs in multiple nested lists

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2

I would like to piggyback on this topic because I’m after the same result.
I believe the solution will be similar to what @jostein_olsen provided here:
(https://forum.dynamobim.com/t/getting-combinations-from-varying-list-lengths/9756):

Insert%20Items
The insertmultiple solution from @Mostafa_El_Ayoubi did not give the right result for me either, unfortunately.