There may be a better way, but the following can help. From org documentation, if you insert more than one blank line before the heading, one blank line will be displayed:
An empty line after the end of a subtree is considered part of it and
will be hidden when the subtree is folded. However, if you leave at
least two empty lines, one empty line will remain visible after folding
the subtree, in order to structure the collapsed view. See the variable
‘org-cycle-separator-lines’ to modify this behavior.
As it says, this can be tweaked (C-h v org-cycle-separator-lines) for the variable doc string:
Number of empty lines needed to keep an empty line between collapsed trees.
If you leave an empty line between the end of a subtree and the following
headline, this empty line is hidden when the subtree is folded.
Org-mode will leave (exactly) one empty line visible if the number of
empty lines is equal or larger to the number given in this variable.
So the default 2 means at least 2 empty lines after the end of a subtree
are needed to produce free space between a collapsed subtree and the
following headline.
If the number is negative, and the number of empty lines is at least -N,
all empty lines are shown.
So if you set the variable to -2, and insert two blank lines, they will be displayed.
