I agree that adding spaces is annoying, for that exact reason. Didn't know it was supposed to be 4, not 2. I did try adding spaces (tried 2 and also 4), but that didn't solve the problem.
I had actually tried inserting
, but it doesn't seem to work:
---
title: "test"
date: "10/2/2020"
output: pdf_document
---
#### Title [header format]<br>
Paragraph text [normal format]
Title [normal format]
Paragraph text [normal format]

I also tried putting it below the line instead of immediately after it, like this:
---
title: "test"
date: "10/2/2020"
output: pdf_document
---
#### Title [header format]
<br>
Paragraph text [normal format]
Title [normal format]
Paragraph text [normal format]
...but that still didn't add a space.
Does that above code work for you if you try knitting it to pdf? I wonder if this is some weird thing with my computer or my version of Tex.