htaccess redirect doesn't work

Questions
1

3.1.6.

I’m currently having problems implementing 301 page redirects on the htaccess file. I tried all sorts of standard redirects and none of them work. The page still goes to 404, and the URL surprisingly changes to /a-kasse/?url=/billig-a-kasse/

I am trying to redirect https://mysite.dk/billig-a-kasse/ to https://mysite.dk/a-kasse


RewriteOptions inherit
### SILVERSTRIPE START ###
<Files *.ss>
	Order deny,allow
	Deny from all
	Allow from 127.0.0.1
</Files>

<Files web.config>
	Order deny,allow
	Deny from all
</Files>

# This denies access to all yml files, since developers might include sensitive
# information in them. See the docs for work-arounds to serve some yaml files
<Files *.yml>
	Order allow,deny
	Deny from all
</Files>

ErrorDocument 404 /assets/error-404.html
ErrorDocument 500 /assets/error-500.html


<IfModule mod_rewrite.c>
	SetEnv HTTP_MOD_REWRITE On
	RewriteEngine On
	RewriteBase '/'

	RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
	RewriteRule ^(.*)$ https://%1/$1 [R=301,L]

	RewriteCond %{HTTPS} off
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
	RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
	RewriteRule ^vendor(/|$) - [F,L,NC]
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
	RewriteRule silverstripe-cache(/|$) - [F,L,NC]
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
	RewriteRule composer\.(json|lock) - [F,L,NC]
	
	RewriteCond %{REQUEST_URI} ^(.*)$
	RewriteCond %{REQUEST_FILENAME} !-f
	RewriteCond %{REQUEST_URI} !\.php$
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
	RewriteRule .* framework/main.php?url=%1&%{QUERY_STRING} [L]
</IfModule>
### SILVERSTRIPE END