How to install mediawiki on a subfolder in Drupal 8 installation?

I have installed Drupal 8 on my example.com website. I want to install mediawiki on a subfolder called example.com/mediawiki. When I try to access example.com/mediawiki it is giving 403 forbidden error. I guess it is because of the rules in .htaccess . How can I fix it so that only example.com/mediawiki is accessible an Mediawiki can be safely installed there? Someone suggested me deleting .htaccess file. But that exposed whole Drupal files to external threats.

If installing mediawiki on a subfolder in Drupal installation is not a good idea, what else could be done ? Suggestions are welcome.

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