WordPress acts strange in combination with htaccess

I have my wordpress installed on https://www.domain.nl/wp.domain.nl
With htaccess in my main directory I rewrite the url https://wp.domain.nl to https://www.domain.nl/wp.domain.nl
When I go to the shorter url I see my wordpress site.

But now I want to change the wordpress- and site address in the general settings to the shorter url, which is causing troubles.
I first only changed the site address, because the other one can be the longer one. If I then go to: https://domain.nl/wp.domain.nl/sample-page/ it shows the error page instead of the page I want to see when I have the longer url filled in.

The htaccess I use for the main domain is:

php_value upload_max_filesize 20M
php_value post_max_size 20M
php_value max_execution_time 200
php_value max_input_time 200

AddHandler application/x-httpd-php .gif .jpg .jpeg .png
php_flag short_open_tag Off
php_flag display_errors off

RewriteEngine on
Options +FollowSymlinks
RewriteBase /

# REDIRECT MAIN DOMAIN
RewriteCond %{HTTP_HOST} ^(www.)?domain.nl$
# /subfolder/
RewriteCond %{REQUEST_URI} !^/www.domain.nl/
# Don't change this line.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# /subfolder/
RewriteRule ^(.*)$ /www.domain.nl/$1
# site
# subfolder/
RewriteCond %{HTTP_HOST} ^(www.)?domain.nl$
RewriteRule ^(/)?$ https://www.domain.nl/ [L]

# SUBDOMAINS to /sub.domain.nl/
RewriteCond %{HTTP_HOST} ^([^.]+)\.domain\.nl$ [NC]
RewriteCond %{HTTP_HOST} !^www\.domain\.nl$ [NC]
RewriteRule ^(.*)$ https://domain.nl/%1.domain.nl/$1 [P,L]

This should do the following:
https://www.domain.nl -> https://www.domain.nl/www.domain.nl
sub.domain.nl -> https://www.domain.nl/sub.domain.nl