Identify duplicates in DT and mark all

Following this post/solution

Is it possible to mark all duplicate rows instead from second onwards?

Thanks

@Jithesh_R sir, I`m tagging you for visibility since you solved in the first place

What would the first row be a duplicate of? There are no rows before it.

But there are rows after.

In my case these rows cary an amount with + and - that are annulling each other. And don’t need them