How to replace the value in same column - PowerBI query editor

I got this query table, now I need one more column that would show all the latest value of unit id which is the true value of the custom and currentUnit column.

data table image

Expected result should be as shown in this screenshot:

expected result image

Any help please!

1. Copy currentUnit to New
2. Replace false with null
3. Transform - Fill up
4. Replace value with null where custom = True
5. Provide sample data in copyable format if you need more detailed instructions