boohoo take a backup of the following files:
composer.json
config.php
extend.php
and your assets folder.
Create a backup of your MySQL Database via SQL Dump.
Download these files.
Delete your Softaculous Installation entirely.
SSH Using Terminal and go to your root directory, run the Flarum Installation Command.
composer create-project flarum/flarum:^1.8.0 .
Change the document root from public_html to public_html/public
Go to your website, complete the Installation Wizard.
Upload and override those files in the Flarum Directory, upload your SQL Dump to your database to recover your website details, and run composer update in your Flarum Directory.
It is critical we detach Softaculous Entirely so it doesn't brick your website with future updates.
It is also critical that we fix the exposure of /public directory so your vulnerable files are not accessible to the browser.
If you don't want to take my word for it: https://lab.migratetoflarum.com/scans/06d008ec-0fea-494f-a0dd-92a2b725310b