Links within linked files don't get signed URLs

[BnjBlm]

I'm using django-storages (S3Boto3Storage) to upload my media files and libraries to S3 buckets.

index.html:

{% load static %}
HElloworld.
<a href="{% static 'blablah.html' %}">blablah.html</a>   

blablah.html:

some dumb text file
dumber_textfile.txt
<a href="blablahblah.html">blablahblah.html</a>

blablahblah.html:

some dumber textfile

• The link to blablah.html on index.html works fine. The URL is the signed: https://mybucketname.s3.amazonaws.com/blablah.html?X-Amz-Algorithm=ALG_REDACTED&X-Amz-Credential=CREDENTIAL_INFO_REDACTED%2Fus-east-2%2Fs3%2Faws4_request&X-Amz-Date=20220804T011840Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=SIGNATURE_REDACTED

• However, the link on blablah.html to blablahblah.html does not work. The URL is unsigned: https://mybucketname.s3.amazonaws.com/blablahblah.html and returns a 403.

How do I get the link to blablahblah.html to be signed without making the file accessible to the public at large? Assume I can't edit the contents of blablah.html (if it were, for example, a CSS file from a library).

edit: updated the problem to a MWE