Finding next empty/non-empty cell in Numbers?

This is a follow-on to how do I move/find the next non empty cell in a column in numbers on a macbook pro is there a short cut because I have the same question and wasn't able to find a reasonable answer. The closest one seemed to be an apple-script solution, but I couldn't figure out how to use that (perhaps because I'm using Numbers v. 5, [on High Sierra, on a MacBook Air] or perhaps because I'm not that versed in using apple-scripts)

My usage scenario is as follows:

I extract a bunch of data from a brokerage statement, and get it nicely formatted in Numbers.

I want to sort the data by the "Amount" column, however, since multiple consecutive transactions for a given security only have the security entered on the first transaction, if I sort the data I'll have a bunch of lines that don't have any security associated with them and the context (from being consecutive) will have been lost due to the sorting.

The simple fix is (before sorting) to find each blank cell in the "Security" column and copy the contents of the cell above into the empty cell - and then repeat the process until there are no empty cells within that column.

The problem is that there doesn't appear to be any [easy?] way to jump down to the next (or previous) empty cell within the column (as there is in Excel):

I think that covers all the possible [logical] key-combinations.

Given the amount of redundancy, if the ability to do what I want exists - it could easily be mapped to one of the various key-combinations.

So the questions remains:

1. Is this ability possible in Numbers?
2. If so, how?
3. If not, why (and can it be implemented in a future version)?