Styles are not loaded

Hi,

This is not the first time I’m installing WordPress, successfully before, not now.
Even with similar configurations can’t find the solution for the problem.

Please see “select a default language image”
As you can see there’s no text.
If I continue the installation, the database is installed, but the next page comes without formatting as well.

I’m running this in a FreeBSD jail, the request comes from another jail where a reverse proxy is working.
Tried this with two different reverse proxy programs and three web servers. The behavior is the same.
I’ve installed wordpress from latest, not as a package of the operating system.

When a mysite.com/php_info.php script is called, php_info() is working, so it seems there’s no problems with php being interpreted.
php is version 7.4.9

When accessing, for example,
https://mysite.com/wp-includes/js/jcrop/jquery.Jcrop.min.css, the webserver returns the contents of the file, so it’s readable.
Same thing for a js file, for example, mysite.com/wp-includes/js/wplink.js

So, I’m not understanding what is wrong with the configuration.
Any help on this?