Codeigniter alongisde Wordpress, both of them on subfolders

Hello,
I am trying to install CI4 alongside WordPress, each of them in an own subfolder.
WordPress should be accessible directly via the main domain (www.example.com)
CodeIgniter should be accessible via www.example.com/codeigniter.
For the future, I would like to have multiple instances of CodeIgniter each on its own folder.
The structure of CodeIgniter has not been changed
My current folder structure looks like this:

Code:

/httpdocs/
│── /wordpress/    (WordPress subdirectory)
│── /codeigniter/  (CodeIgniter subdirectory)
│── index.php   (redirects to /wordpress/index.php)
│── .htaccess

The .htaccess under httpdocs (created by ChatGPT) looks like this:

Code:

RewriteEngine On

# Exception for CodeIgniter so that it is not overwritten by WordPress
RewriteCond %{REQUEST_URI} ^/codeigniter/ [NC]
RewriteRule .* - [L]

# Redirect all requests to WordPress (unless it is a real file/directory)
RewriteCond %{REQUEST_URI} !^/wordpress/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /wordpress/$1 [L]

# WordPress default rules (customised for subfolders)
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /wordpress/index.php [L]

.htaccess under www.example.com/codeigniter:

Code:

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteRule ^(.*)$ public/$1 [L]
</IfModule>

<FilesMatch "^\.">
    Require all denied
    Satisfy All
</FilesMatch>

.htaccess under www.example.com/codeigniter/public:

Code:

# Disable directory browsing
Options -Indexes

# ----------------------------------------------------------------------
# Rewrite engine
# ----------------------------------------------------------------------

# Turning on the rewrite engine is necessary for the following rules and features.
# FollowSymLinks must be enabled for this to work.
<IfModule mod_rewrite.c>
Options +FollowSymlinks
RewriteEngine On


# If you installed CodeIgniter in a subfolder, you will need to
# change the following line to match the subfolder you need.
# http://httpd.apache.org/docs/current/mod/mod_rewrite.html#rewritebase
RewriteBase /codeigniter/

# Redirect Trailing Slashes...
#RewriteCond %{REQUEST_FILENAME} !-d
#RewriteCond %{REQUEST_URI} (.+)/$
#RewriteRule ^ %1 [L,R=301]

# Rewrite "www.example.com -> example.com"
#RewriteCond %{HTTPS} !=on
#RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
#RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]

# Checks to see if the user is attempting to access a valid file,
# such as an image or css document, if this isn't true it sends the
# request to the front controller, index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([\s\S]*)$ index.php/$1 [L,NC,QSA]

# Ensure Authorization header is passed along
RewriteCond %{HTTP:Authorization} .
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
</IfModule>

<IfModule !mod_rewrite.c>
# If we don't have mod_rewrite installed, all 404's
# can be sent to index.php, and everything works as normal.
ErrorDocument 404 index.php
</IfModule>

# Disable server signature start
ServerSignature Off
# Disable server signature end

BTW: the base_url has been set to 'http://www.example.com/codeigniter/'
The problem I am facing is that CodeIgniter uses relative links (e.g.  <a href="/about">) that now point to www.example.com/about instead of www.example.com/codeigniter/about
The only solution I have found for me is to use base_url() on each link and form actions.
Is there any other solution to this?