papaja: modify spacing under headings - r

Question

I am using the package papaja to write an APA-formatted manuscript with R markdown.
I would like to modify the default spacing under headings (it's presently too large for my taste).
As shown on the sample picture below (document rendered as pdf), spacing around the headings is more than double spacing.
I've looked at different solutions, including the \raggedbottom option in my header or the latex function \titlespacing from the package titlesec (https://tex.stackexchange.com/questions/53338/reducing-spacing-after-headings), but I haven't been able to make it work. I'm a newbie when it comes to Latex.
Below is my current header:
header-includes:
- \usepackage{dcolumn}
- \usepackage{setspace}
- \AtBeginEnvironment{tabular}{\singlespacing}
- \AtBeginEnvironment{lltable}{\singlespacing}
- \AtBeginEnvironment{tablenotes}{\singlespacing}
- \captionsetup[table]{font={stretch=1.5}}
- \captionsetup[figure]{font={stretch=1.5}}
- \raggedbottom
Note: I hesitated between posting this question here or on the Stack Exchange - Latex forum. But because of R markdown and R package papaja specificities, I decided to post it here.
Below is a full reproducible example.
---
title : "The title"
shorttitle : "SHORT TITLE"
author:
- name : "First Author"
affiliation : "1"
corresponding : yes # Define only one corresponding author
address : "Postal address"
email : "my#email.com"
affiliation:
- id : "1"
institution : "First affiliation"
floatsintext : no
figurelist : no
tablelist : no
footnotelist : no
linenumbers : no
mask : no
draft : no
documentclass : "apa6"
classoption : "man"
output : papaja::apa6_pdf
header-includes:
- \raggedbottom
---
# Section
## Subsection
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
### Subsubsection
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
## Subsection
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
# Section
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.