Problems moving from directory to root

Hi

I have gone through countless threads but none of them seem to work. Here is what I have done so far:

Blog was hosted on https://www.bisonsridehard.com/home which I tried moving to the root.

Before I did that I changed the WordPress URL and Site URL as mentioned in https://codex.www.ads-software.com/Moving_WordPress

I had changed the index.php earlier which I changed back to the original settings. Set the permissions of the .htaccess file to 666 as mentioned in the codex.

But I have been getting the Internal Server 500 Error. I understand that this is an issue with the .htaccess file from all the threads I have read.

I am at this point unable to login to the dashboard to make any changes but I have full access to the DB and FTP.

Please advise!