DarkXero I looked how your server is organized.
You don't have a index.php file inside the public Flarum folder even the .htaccess.
Those file are outside of the public folder in your install, in the public_html folder.
Even the content of the index.php file seems to be totally different from mine.
You installed Flarum in a public_html folder where you have also other applications installed.
This seems to be a caos for me.
Seems also you don't have a recent backup and this is a problem to try to help you.
Also, if you are limited in your hosting because is shared and you have not full server access, can be hard manage well Flarum.
I think I'm unable to help you, sorry.
Your issue seems to be caused by litespeed, see: https://techxero.com/blog/27-startallback-for-windows-11-is-great
I suggest to ask help also to LiteSpeed.
You can may try to search on Google "litespeed 404 error"