Changing the root folder via .htaccess

Hello , I’m using Apache with yii2 and i have 2 route /en , /ar i want app by default open to /ar

Options -Indexes

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS} !on [OR]
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ https://www.example.com%{REQUEST_URI} [R=301,L]

RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://www.example.com%{REQUEST_URI} [R=301,L]
</IfModule>

RewriteEngine on
#RewriteCond %{HTTPS} !=on
RewriteCond %{HTTP_HOST} ^128.199.50.203$
RewriteCond %{HTTP_HOST} ^example\.com [NC]
RewriteRule ^(.*)$ https://www.example.com%{REQUEST_URI} [R=301,L]


# Preventing Redirect loop
RewriteRule ^(frontend|backend)/web/ - [L]
RewriteRule ^(common)/web/ - [L]

RewriteCond %{REQUEST_URI} !^/api
RewriteCond %{REQUEST_URI} !^/admin
RewriteCond %{REQUEST_URI} !^/app
RewriteCond %{REQUEST_URI} !^/backend
RewriteCond %{REQUEST_URI} !^/uploads

RewriteRule ^(.*)$ /frontend/web/index.php/$1 [L]